DETERMINATION OF CONTACT ANGLES OF POWDERS BY … · DETERMINATION OF CONTACT ANGLES OF POWDERS BY...

DETERMINATION OF CONTACT ANGLES OF POWDERS BY

CAPILLARIC DEWATERING OF FILTER CAKES

A THESIS SUBMITTED TO

THE GRADUATE SCHOOL OF NATURAL AND APPLIED SCIENCES

OF

MIDDLE EAST TECHNICAL UNIVERSITY

BY

ÖZLEM DENİZ ERATAK

IN PARTIAL FULFILLMENT OF THE REQUIREMENTS

FOR

THE DEGREE OF MASTER OF SCIENCE

IN

DEPARTMENT OF MINING ENGINEERING

JANUARY 2005

I hereby declare that all information in this document has been obtained and presented in accordance with academic rules and ethical conduct. I also declare that, as required by these rules and conduct, I have fully cited and referenced all material and results that are not original to this work.

Name, Last name :

Signature :

iii

ABSTRACT

DETERMINATION OF CONTACT ANGLES OF POWDERS BY

CAPILLARIC DEWATERING OF FILTER CAKES

Eratak, Özlem Deniz

M. Sc., Department of Mining Engineering

Supervisor: Prof. Dr. Çetin Hoşten

January 2005, 140 pages

Solid-liquid contact angle is an important parameter in many particulate processes

of the mineral, ceramic and chemical industries. In particular, modification of the

contact angle through surface active agents plays a crucial role in froth flotation

of minerals. In the case of flat solid surfaces, direct measurement of the contact

angle is possible. However, such flat surfaces can not be obtained with finely

divided solids typically encountered in flotation applications. Then, indirect

methods based on powder beds as thin layers of powders deposited on glass

plates or packed columns are used for the determination of apparent contact

angles.

This thesis presents an alternative novel method based on the capillaric

dewatering of filter cakes for the measurement of the receding contact angle and

correlates the contact angles measured as such with column wicking and micro-

flotation test results of zircon and rutile mineral particles. The experimental

procedure is simple and fast. The results have proven that the proposed method is

reliable and give a good measure of the contact angle in the absence and presence

of surface active non-wetting agents.

Keywords: Contact Angle, Cake Dewatering, Column Wicking, Microflotation

iv

ÖZ

FİLTRE KEKLERİNİN SUSUZLANDIRILMASI ÖZELLİKLERİNDEN

YARARLANARAK KATI TANECİKLERİNİN SIVILARLA TEMAS

AÇILARININ BELİRLENMESİ

Eratak, Özlem Deniz

Yüksek Lisans, Maden Mühendisliği Bölümü

Tez Yöneticisi: Prof. Dr. Çetin Hoşten

Ocak 2005, 140 sayfa

Katı-sıvı temas açısı, bir çok mineral,seramik ve kimya endüstrilerinin katı

tanecikli işlemlerinde önemli bir parametredir. Özellikle de, yüzey aktif

reaktiflerin ilavesi ile değişen temas açısı, minerallerin köpüklü flotasyonunda

çok önemli bir rol oynar. Katı yüzeyi düz olduğu takdirde, temas açısının

doğrudan ölçümü mümkündür. Ancak, bu tür düz yüzeylere, flotasyon

uygulamalarında toz haline gelmis katılarda rastlamak mümkün değildir. Bu

durumda, temas açıları ince tane yataklarına veya kolonlarına dayanan

yöntemlerle dolaylı olarak belirlenir.

Bu tezde, temas açısı ölçümü için filtre keklerinin kapiler susuzlandırılmasına

dayanan yeni bir yöntem önerilmekte ve sonuçları kolona emme ve mikro

flotasyon yöntemleri ile karşılaştırılmaktadır. Deneysel yöntem basit ve hızlı olup

elde edilen sonuçlar, yüzey aktif maddelerin yokluğunda veya varlığında

güvenilir temas açısı değerleri verdiğini göstermiştir.

Anahtar Kelimaler: Temas Açısı, Filtre Keki Susuzlandırma, Kolona Emme,

Mikro Flotasyon

v

To My Grandparents

vi

ACKNOWLEDGEMENTS

I wish to express my deepest gratitude to my supervisor Prof. Dr. Çetin Hoşten

for his valuable advice and guidance of this work. I wish also to express my

special thanks and gratitude to Prof. Dr. Ali İhsan Arol, Prof. Dr. Cahit

Hiçyılmaz, Prof. Dr. Gülhan Özbayoğlu and Prof. Dr. Ümit Atalay for their

suggestions and comments.

I want to express my appreciation to my friend Ayşe Yasemin Yeşilay for

sharing her ideas with me, helping me for this thesis and her great friendship

and I wish also to express my thanks to research assistants for their help.

I wish to thank to technical staff of Department of Mining Engineering,

especially Tahsin Işıksal, Tuncer Gençtan, Mehmet Çakır, Aytekin Arslan and

İsmail Kaya.

I would like to sincerely thank to my family for their support and help

throughout this job.

Especially, I would like to give my special thanks to Hidayet Doğan for his

support, patience, partnership and understanding

The grant provided by the research fund of the Middle East Technical

University through the project BAP-2002-03-05-01 is gratefully

acknowledged.

vii

TABLE OF CONTENTS

PLAGIARISM................................................................................... iii

ABSTRACT ...................................................................................... iv

ÖZ ...................................................................................................... v

ACKNOWLEDGEMENTS ............................................................ vii

TABLE OF CONTENTS ................................................................ viii

LIST OF TABLES ........................................................................... x

LIST OF FIGURES ......................................................................... xx

CHAPTER

INTRODUCTION ............................................................................ 1

1.1 Objective of Thesis ...................................................................... 4

THEORETICAL BACKGROUND ............................................... 5

2.1 General ......................................................................................... 5

2.2 Contact Angle and Wetting .......................................................... 5

2.2.1 Adhesion, cohesion and spreading .................................... 8

2.2.2 Critical surface tension of wetting .................................... 9

2.3 Contact Angle Measurements ...................................................... 10

2.3.1 Direct measurements of contact angle .............................. 10

2.3.2 Column wicking method ................................................... 11

2.3.3 Thin layer wicking method ............................................... 12

2.3.4 Hysteresis in contact angle ............................................... 13

2.4 The theory of the proposed method of contact angle

measurement ...................................................................................... 15

EXPERIMENTAL MATERIAL AND METHODS ..................... 18

3.1 Preparation of Samples ................................................................ 18

viii

3.2 Reagents ....................................................................................... 19

3.3 Experimental Procedure and Methods ......................................... 19

3.3.1 Dewatering of filter cakes ................................................. 19

3.3.2 Column Wicking ............................................................... 20

3.3.3 Microflotation Experiments .............................................. 22

EXPERIMENTAL RESULTS AND DISCUSSION ..................... 23

4.1 Capillaric dewatering experiments ............................................... 23

4.1.1 Experiments with zircon ................................................... 23

4.1.2 Experiments with Rutile ................................................... 32

4.2 Column Wicking Experiments ..................................................... 38

4.3 Microflotation Experiments ......................................................... 48

CONCLUSIONS .............................................................................. 52

REFERENCES ................................................................................. 54

APPENDICES .................................................................................. 58

ix

LIST OF TABLES

4.1. The contact angle and k.cosθ values for the zircon sample as

obtained from cake dewatering tests using water-methanol

mixtures..................................................................................................

28

4.2. The contact angle and k.cosθ values from the cake dewatering

experiments with -150+200 mesh zircon by using 10-5 M

dodecylamine at various pH values of the solution. ..............................

30

4.3. The contact angle and k.cosθ values for the rutile sample as

obtained from cake dewatering tests using water-methanol mixtures....

37

4.4. Contact angles for rutile obtained from dewatering experiments

using dodecyl amine and sodium dodecyl sulfate solutions at various

pH values................................................................................................

38

4.5. The advancing and receding contact angles of zircon with water-

methanol mixtures in the column wicking experiments.........................

42

4.6. The advancing and receding contact angles of rutile with water-

methanol mixtures in the column wicking experiments.........................

42

4.7. The advancing and receding contact angles of zircon from

column wicking (θA) and cake dewatering experiments (θR)...............

44

4.8. The advancing and receding contact angles of rutile from column

wicking (θA) and cake dewatering experiments (θR)............................

47

A 1. -100+200 mesh quartz experimented with methanol...................... 58

A.2. -100+200 mesh quartz experimented with water............................ 58

A.3. -100+200 mesh quartz experimented with 80% methanol............. 59



x




A.9. -100+200 mesh quartz experimented with water............................ 62

A.10. -200+400 mesh quartz experimented with water.......................... 62

A.11. -100+200 mesh quartz experimented with hexane....................... 63



A.14. -100+200 mesh quartz experimented with water.......................... 64

A.15. -150+200 mesh zircon experimented with water.......................... 65

A.16. -150+200 mesh zircon experimented with methanol.................... 65

A.17. -150+200 mesh zircon experimented with methanol.................... 66

A.18. -150+200 mesh zircon experimented with 10% methanol........... 66












A.30. -150+200 mesh zircon experimented with 5.10-5 M DA at

pH 4.......................................................................................................

72


pH 4.......................................................................................................

73

xi


pH 6.......................................................................................................

73


pH 6....................................................................................................... 74

A.34. -150+200 mesh zircon experimented with 5.10-5 M DA at pH 8 74


pH 10......................................................................................................

75


pH 10......................................................................................................

75

A.37. -150+200 mesh zircon experimented with 10-5 M DA at pH 4... 76






A.43. -150+200 mesh zircon experimented with 10-5 M DA at pH 10. 79

A.44. -150+200 mesh zircon experimented with 10-5 M DA at pH 10. 79

A.45. -150+200 mesh zircon experimented with 10-4 M SDS at pH 2.. 80




A.49. -150+200 mesh zircon experimented with 5.10-5 M SDS at

pH 2.........................................................................................................

82


pH 4.........................................................................................................

82


pH 6.........................................................................................................

83

xii


pH 8......................................................................................................... 83





A.57. -150+200 mesh rutile experimented with water........................... 86

A.58. -150+200 mesh rutile experimented with water........................... 86

A.59. -150+200 mesh rutile experimented with methanol..................... 87

A.60. -150+200 mesh rutile experimented with methanol..................... 87

A.61. -150+200 mesh rutile experimented with 10% methanol............. 88












A.73. -150+200 mesh rutile experimented with 10-4 M DA at pH 4..... 94






A.79. -150+200 mesh rutile experimented with 10-4 M DA at pH 10... 97

xiii


A.81. -150+200 mesh rutile experimented with 5.10-5 M DA at pH 4.. 98






A.87. -150+200 mesh rutile experimented with 5.10-5 M DA at pH 10 101









A.96. -150+200 mesh rutile experimented with 10-4 M SDS at pH 2... 105




A.100. -150+200 mesh rutile experimented with 5.10-5 M SDS at

pH 2........................................................................................................

107


pH 4........................................................................................................

108


pH 6........................................................................................................

108


pH 8........................................................................................................

109

A.104. -150+200 mesh rutile experimented with 10-5 M SDS at pH 2 109

xiv




B.1. -150+200 mesh zircon experimented with water............................ 112

B.2. -150+200 mesh zircon experimented with methanol...................... 112

B.3. -150+200 mesh zircon experimented with hexane......................... 113

B.4. -150+200 mesh zircon experimented with formamide................... 113

B.5. -150+200 mesh zircon experimented with 10% methanol.............. 114





B.10. -150+200 mesh zircon experimented with 80% methanol............ 116

B.11. -150+200 mesh zircon experimented with 5.10-5 M DA at pH 4 116



B.14. -150+200 mesh zircon experimented with 5.10-5 M DA at

pH 10.......................................................................................................

118

B.15. -150+200 mesh zircon experimented with 10-5 M DA at pH 4... 118



B.18. -150+200 mesh zircon experimented with 10-5 M DA at pH 10 120

B.19. -150+200 mesh zircon experimented with 10-5 M SDS at pH 2 120

B.20. -150+200 mesh zircon experimented with 5.10-5 M SDS at

pH 2.........................................................................................................

121

B.21. -150+200 mesh zircon experimented with 10-4 M SDS at pH 2 121

B.22. -150+200 mesh rutile experimented with water........................... 122

B.23. -150+200 mesh rutile experimented with methanol..................... 123

B.24. -150+200 mesh rutile experimented with 10% methanol............. 123

xv






B.30. -150+200 mesh rutile experimented with 10-4 M DA at pH 4..... 126



B.33. -150+200 mesh rutile experimented with 10-4 M DA at pH 10... 127

B.34. -150+200 mesh rutile experimented with 5.10-5 M DA at pH 4.. 127



B.37. -150+200 mesh rutile experimented with 5.10-5 M DA at pH 10 128




B.41. -150+200 mesh rutile experimented with 10-5 M DA at pH 10... 130

C.1. -150+200 mesh zircon experimented with water............................ 131

C.2. -150+200 mesh zircon experimented with 10-3 M DA at different

pH values

................................................................................................ 131


pH values

................................................................................................ 131

C.4. -150+200 mesh zircon experimented with 5.10-5 M DA at

different pH values.................................................................................

132


pH values

................................................................................................ 132

C.6. -150+200 mesh zircon experimented with 10-3 M SDS at

different pH values..................................................................................

132

xvi



132

C.8. -150+200 mesh zircon experimented with 5.10-5 M SDS at


133



133

C.10. -150+200 mesh rutile experimented with 10-3 M DA at


133



133

C.12. -150+200 mesh rutile experimented with 5.10-5 M DA at


134



134

C.14. -150+200 mesh rutile experimented with 10-3 M SDS at


134



134

C.16. -150+200 mesh rutile experimented with 5.10-5 M SDS at


135



135

D.1. The reproducibility of -150+200 mesh zircon experimented with

10% methanol......................................................................................... 136

D.2 The reproducibility of -150+200 mesh zircon experimented with

25% methanol....................................................................................... 136


40% methanol..................................................................................... 136

xvii


50% methanol..................................................................................... 136


65% methanol..................................................................................... 136


80% methanol.....................................................................................

137


5.10-5 M DA at pH 4.............................................................................. 137


5.10-5 M DA at pH 6.............................................................................. 137


5.10-5 M DA at pH 8.............................................................................. 137

D.10. The reproducibility of -150+200 mesh zircon experimented

with 5.10-5 M DA at pH 10.................................................................... 137


with 10-5 M DA at pH 4....................................................................... 137


with 10-5 M DA at pH 6....................................................................... 138


with 10-5 M DA at pH 8....................................................................... 138


with 10-5 M DA at pH 10....................................................................... 138

D.15. The reproducibility of -150+200 mesh rutile experimented with

water............................................................................................... 138


10% methanol................................................................................ 138


25% methanol................................................................................ 138

xviii


40% methanol................................................................................ 138


50% methanol................................................................................ 139


65% methanol................................................................................

139


10-4 M DA at pH 4................................................................................ 139


10-4 M DA at pH 6................................................................................ 139


10-4 M DA at pH 8................................................................................ 139


10-4 M DA at pH 10.............................................................................. 139


5.10-5 M DA at pH 4.............................................................................. 139


5.10-5 M DA at pH 6.............................................................................. 140


5.10-5 M DA at pH 8.............................................................................. 140

xix

LIST OF FIGURES

2.1. The contact angle formed by solid, liquid and gas ......................... 6

3.1. The illustration of capillaric dewatering experiments .................... 21

3.2. The illustration of column wicking experiments ............................ 21

3.3. The illustration of Hallimond tube. ................................................ 22

4.2. Residual cake saturation versus k.cosθ plots for -150 + 200 mesh

zircon when methanol or a water-methanol mixture was used as the

liquid. ..................................................................................................... 25



liquid. ..................................................................................................... 25



liquid. ..................................................................................................... 26



liquid. ..................................................................................................... 26



liquid. ..................................................................................................... 27



liquid. ..................................................................................................... 27

xx

4.8. Contact angle values obtained with zircon by using methanol-

water mixtures. ...................................................................................... 28


zircon when 10-5M dodecylamine solution was used as the liquid. ..... 29

4.10. The contact angle values for the -150+200 mesh zircon sample

in contact with 10-5M dodecylamine solutions at various pH values. .. 30

4.11. Residual cake saturation versus k.cosθ plots for -150 + 200

mesh zircon when 10-4M sodium dodecyl sulfate solution was used as

the liquid. ............................................................................................... 32


mesh rutile when water or methanol was used as the liquid. ................ 33


mesh rutile when methanol or a water-methanol mixture was used as

the liquid. ............................................................................................... 33



the liquid. ............................................................................................... 34



the liquid. ............................................................................................... 34



the liquid. ............................................................................................... 35



the liquid. ............................................................................................... 35

xxi



the liquid. ............................................................................................... 36

4.19. Surface tension values of methanol mixtures. .............................. 36

4.20. Column wicking plots for -150+200 mesh zircon particles with

completely-wetting organic liquids and partially-wetting liquid water. 40

4.21. Column wicking plots for -150+200 mesh rutile particles with

completely-wetting organic liquids and partially-wetting liquid water. 40


water-methanol mixtures. ...................................................................... 41


water-methanol mixtures. ...................................................................... 41


10-5 M dodecyl amine at different pH values. ...................................... 43


10-5 M dodecyl amine at different pH values. ....................................... 43


different concentrations of sodium dodecyl sulfate at pH 2. ................. 44




5x10-5 M dodecyl amine at different pH values. .................................. 45




different concentrations of sodium dodecyl sulfate at pH 2. .................

46

4.31. Flotation response of -150+200 mesh zircon with dodecyl amine

at different pH values. R denotes repeat experiments. .......................... 48

xxii

4.32. Flotation response of -150+200 mesh zircon with sodium

dodecyl sulfate at different pH values. R denotes repeat experiments... 49

4.33. Flotation response of -150+200 mesh rutile with dodecyl amine

at different pH values. R denotes repeat experiments. .......................... 49

4.34. Flotation response of -150+200 mesh rutile with sodium dodecyl

sulfate at different pH values. R denotes repeat experiments. ............... 50

xxiii

CHAPTER 1

INTRODUCTION

The solid-liquid contact angle is used as a measure of wettability and the surface

free energy of solids in many diverse fields such as mineral and coal benefication,

petroleum engineering, and the manufacture of pharmaceutical powders,

cosmetics, pigments, paints and paper. Therefore, contact angle measurements are

fundamental to many processes. Contact angle measurements on finely divided

solids are much more difficult than those on moderately large, uniform solid

surfaces, but the former is often more desired and more important since many

industrial applications involve processing of particulate solids. For example, the

froth flotation separation of minerals is controlled to a large extent by the relative

wettabilities of finely divided mineral particles in an aqueous suspension, which

generally requires the use of surface active agents (surfactants) to selectively

modify the wettability or the contact angle of highly irregular mineral particles.

Two general methods exist for determining powder contact angles [Adamson,

1967]: (i) the Washburn equation (or dynamic) method which is based on the rate

of liquid flow into a packed bed or porous plug of particulate solids; (ii) the

Bartell (or static) method which is based on equilibrium measurements of the

capillary pressure increment required to prevent liquid from penetrating the

packed bed. The principles of the measurement methods are simple but they both

suffer some experimental and fundamental difficulties. One experimental

difficulty is that both methods in their simplest form require visual observation of

the wetting liquid from inside the porous bed, which may be skewed in the case

1

of irregulary shaped polydisperse particles or its exact position may not be

clearly visible due to wall effects of the enclosing glassware. A fundamental

limitation with measurements in packed beds is the assumption that the packing

density will not change with nature of the penetrating ( or receding) liquid, as the

methods require an additional calibrating liquid, perfectly wetting the solids, to

determine the effective pore radius in the bed. This limitation is of more concern

in systems where surfactants are present in the penetrating liquid. Flocculation or

dispersion produced by surfactant solutions can change the packing density.

Furthermore, the depletion of surfactant molecules from the liquid phase by

adsorption on the powder surface area in the region of liquid front can seriously

affect the contact angle and the liquid surface tension in rate-measuring methods.

Modified versions to circumvent difficulties of the two general measurement

methods have been reported in the literature. Good R.J. et al (1993) developed the

thin layer wicking method to measure the rate of advance of wetting liquids

through a thin layer of solid particles deposited onto a glass slide. This method

uses the Washburn equation to determine the cosine of the contact angle and

requires calibration tests with a perfectly wetting liquid to calculate the effective

interstitial pore radius of the thin layer. Chibowski and Perea-Carpio (2001)

developed a technique involving the measurement of the weight of liquid

penetrating into a powder bed, instead of monitoring the movement of the liquid

front, for the determination of the solid surface free-energy components, but did

not propose to derive the contact angle from such data. The powder contact angle

device of Dunstan and White (1986) and that of Diggins et al. (1990) both used

the Bartell concept; however, rather than applying an external pressure difference

to prevent capillary rise, the penetrating liquid was allowed to rise causing a

gradual increase in the pressure of air enclosed above the wetting front. The

2

capillary pressure was calculated by measuring the air pressure to stop the rise of

liquid up the packed bed and subtracting any hydrostatic head, if present.

Capillary pressure determinations in packed beds are equilibrium measurements

with incremental changes in the applied air pressure and generally require long

equilibrium times. Furthermore, most of the practical wetting or dewetting

processes are of nonequilibrium nature. For example, the act of particle-air

bubble attachment in froth flotation and filter cake dewatering upon rapid

application of a certain pressure difference is governed by nonequilibrium

receding contact angles. Therefore, a simple, fast method combining the dynamic

and the static methods of the contact angle measurement may be of practical

value for determining apparent contact angles.

The motivation for the current study was to determine apparent receding contact

angles of particulate solids from irreducible (or residual) moisture contents of

filter cakes dewatered at different instantaneous vacuum levels. A filter cake

fully saturated with liquid is said to be in the capillary state. Upon instantaneous

application of vacuum greater than the negative capillary pressure at the air-liquid

interface, liquid displacement and air fingering of the cake begins. However, for a

given vacuum level, a certain portion of the liquid will not drain out of the cake

irrespective of drainage time. At this irreducible saturation level, liquid and air

may have two distinct configurations within the cake. At relatively low applied

pressure differences, the funicular state is reached in which a continuous network

of liquid exists in equilibrium with air above the jagged liquid front. At higher

pressure differences, further drainage of liquid occurs until there is insufficient

liquid to form a continous liquid phase. Air breaks through the cake and the filter

medium, if the pores of the latter are not small enough to cause very high

capillary pressures. Eventually the pendular state is reached in which small lenses

of liquid exist at points of particle contact. The range of the applied pressure

3

differences corresponding to the funicular state will depend on the particle size

and its distribution and the solid-liquid contact angle. As the size distribution

becomes wider, there will also be a wider variation of pore radii in the filter cake,

consequently, the funicular state will extend over a wider pressure range.

1.1 Objective of Thesis

The aim of the present work was to develop a simple, fast technique for the

determination of apparent contact angles of particulate solids from

nonequilibrium filter cake drainage tests. The residual saturation of filter cakes in

the funicular state of cake drainage was correlated with the applied vacuum to

determine the contact angle of particulate solids constituting the filter cake.

4

CHAPTER 2

THEORETICAL BACKGROUND

2.1 General

The contact angle is a very important property of solid-liquid-gas or solid–

liquid–liquid interfaces. Contact angle plays a major role in technological,

biological, mineral, ceramic, chemical, pharmaceutical and environmental

processes and can define the surface tension of the solid on which it is formed.

Powder contact angle measurement is also an important parameter in processes as

diverse as flotation, wet grinding and the manufacture of pigments, paints and

cosmetics [Iveson, Holt and Biggs, 2000].

Direct measurement of contact angle of powders is impossible. The very simple

direct measurement of contact angles of a liquid drop on a flat and smooth solid is

not applicable to small powder particles [Siebold et al, 2000]. Thus, scientists are

working on indirect methods to determine the contact angle of powders so as to

characterize the wettability of solids.

2.2 Contact Angle and Wetting

Angle which is formed between liquid-vapor interface and liquid-solid interface

at the solid-liquid-vapor three-phase contact line is defined as the contact angle.

5

Figure 2.1. The contact angle formed by solid, liquid and gas.

The Laplace equation and the Young equation are the two fundamental equations

that describe the capillarity phenomenon and the contact angle, respectively:

( 21 /1/1 RRP LV +=∆ )γ [1]

SLSVLV γγθγ −=cos [2]

where

LVγ is the liquid-vapor surface tension,

SVγ is the solid-vapor surface tension,

SLγ is the solid-liquid surface tension,

1R and are the radii of the curvature, 2R

θ is the equilibrium contact angle.

From Young’s equation [Finch, Smith, 1979]:

If SLSVLV γγγ −> a three- phase contact is established.

If SLSVLV γγγ −< no vapor-solid contact is established.

6

The solid-liquid interfacial tension and liquid-vapor interfacial tension must be

high and solid-vapor interfacial tension must be low for good flotation.

The surface free energy of solids appears a very important parameter determining

the interfacial properties in solid-liquid and solid-gas interfaces [Biliński, Holysz,

1999]. Today, there are also some problems in determining the surface free

energy of solids, and scientists made assumptions to formulate the value of the

surface free energy. The first assumption is that the surface free energy is the sum

of the dispersion (γsd) and the polar (γs

p) interactions, and the other new

formulation was proposed in the late 80’s by van Oss et al. on the surface free

energy, as well as a determination of the energy components from contact angles.

The authors for the first time gave an expression for Lewis acid-base interactions

(AB), i.e., electron donor and electron acceptor interactions, which in most

systems are due to the hydrogen bonding [Chibowski, Carpio, 2001]. According

to these formulations, the surface energy of the solid is given by

)(2 −++=+= SSLW

SAB

SLW

SS γγγγγγ [3]

where

LW

Sγ is the apolar Lifshitz-van der Waals +

Sγ is the electron acceptor interactions −

Sγ is the electron donor interactions

7

The solid liquid interaction is given by the following equation :

⎥⎦⎤

⎢⎣⎡ ++−+= +−−+ )()()(2 SSSS

LWL

LWSLSSL γγγγγγγγγ [4]

when combined with the Young equation

SLaLS γθγγ += cos. [5]

and

aLSSL W−+= γγγ [6]

where θa is the advancing contact angle and,

Wa is the work of adhesion

⎥⎦⎤

⎢⎣⎡ ++=+= +−−+ )()()(2)cos1( LSLS

LWL

LWSaLaW γγγγγγθγ [7]

These equations help to determine the surface properties and the surface free

energy components.

2.3.1 Adhesion, cohesion and spreading

When generating 2 new interfaces of unit area the free energy is

∆G = 2γA = WAA [8]

WAA is the work of cohesion and it measures the attraction between the molecules

of the liquid. The free energy change between two liquids is given by

8

∆G = WAB = γA + γB-γAB [9]

Where WAB is the work of adhesion and measures the attraction between two

different phases.

The difference between the work of adhesion and cohesion of two substances is

the spreading coefficient of B on A

SB/A = WAB-WBB [10]

If SB/A is positive, substance A spreads and if SB/A is negative, it retreats. If the

vapor phase replaced by another phase like oil the equation will be

γow cosθ = γso - γsw [11]

2.3.2 Critical surface tension of wetting

When cosθ =1, the liquid completely wets the solid. The value of the γLV is the

critical surface tension of the solid and γc represents this value.

For Liquids:

If γLV > γc there will be a contact angle,

If γlv < γc the liquid will wet the solid,

9

and the cosθe is related to γlv by

cosθe = 1 – b (γlv - γc) [12]

where b is the constant, and the cosθ versus γlv plot is the Zisman plot and the

equation is the Zisman equation.

2.3. Contact Angle Measurements

2.3.1 Direct measurements of contact angle

It is observed that in most instances a liquid placed on a solid will not wet but it

remains as a drop having a definite angle of contact between the liquid and solid

phases [Adamson, 1967]. The direct measurement of the contact angles can be

applicable for large sample of solids. The tilting plate method has given the most

reproducible and probably the most accurate contact angle values. A several

centimeter wide plate of the solid dips into the liquid, and its position is altered by

means of an adjustable mount until the angle such that the liquid surface appears

to remain perfectly flat right up to the surface of the solid [Adamson, 1967].

The other technique for measuring the contact angles directly is the sessile drop

method. Sessile drop technique is a widely used for measuring the direct contact

angle. For this measurement the surface of the solid must be smooth and clean

then the solid dips into the liquid and on the surface a bubble is formed, the angle

between sessile drop and solid can be read from goniometer.

10

2.3.2 Column wicking method

The contact angle of fine particles can be measured by column wicking method.

This method is based on the penetration of liquid into the porous structure

measuring the change of surface energy. In this technique powdered solids

packed into a capillary tube and it is immersed in a liquid of known surface

tension. Then, the rise of liquid into the powdered solids is observed. The contact

angle can be found from the height of the liquid as a function of penetration time.

Column wicking method is based on Poiseuille’s law:

=νdtdh =

η8

2DR

hP∆ [13]

where

ν = rate of liquid penetration

h = height reached by the liquid

t = penetration time

DR = hydrodynamic radius of pores

η = viscosity of the liquid

P∆ = the difference of pressure

After integration of the equation, the Washburn equation can form:

2h = η

θγ

2

cosLr t [14]

11

There are some modifications of the column wicking method which are based on

the equation

W = 2πrγcosθ [15]

When the contact angle is zero:

W = mg = 2πrγ [16]

Where m is the mass of the liquid and g is the gravitational acceleration.

If there is a contact angle liquid enters the capillary at dynamic advancing contact

angle, the equation will be:

ma g = 2πrγcos θa = 2rπ∆Ga [17]

where ∆Ga the specific free energy change. For the receding contact angle, the

above equation takes the form

mrg = 2πrγcosθr = 2rπ∆Gr [18]

2.3.3 Thin layer wicking method

Thin layer technique is based on the phenomena of a liquid penetration (wicking)

into a solid porous layer deposited on a glass plate, e.g. microscope slide. The

surface free energy components are then calculated from the proper form of the

Washburn equation [Teixeira, et al, 1998].

12

In the thin layer technique, the powdered solid deposited on a microscopic slide

in the form of aqueous slurry then the sample is dried and one side of the slide is

immersed in a liquid in the vertical position and the liquid penetrates into the

solid slowly.

Thin layer wicking method also uses the Washburn equation. The only problem

in these experiments is the calculation of r value. r value can be determined from

the low energy liquids such as hexane, benzene, methanol, formamide.

The methods which are based on Washburn equation give only advancing contact

angles rather than equilibrium contact angles.

Contact angle can be measured directly by compressing the powders into pellets

but this method is not recommended. The surface properties such as surface

roughness, liquid adsorption and porosity can change in the pressing phase so the

measurement of contact angle using pellets is only an assumption.

2.3.4 Hysteresis in contact angle

From the contact angle studies, it is observed that the receding and advancing

contact angles can be different. The past experiments show that θA (Advancing

Contact Angle) should be bigger than θR (Receding Contact Angle) and the

difference between θA and θR called contact angle hysteresis. The effect can be

quite large, for water on surfaces of minerals the advancing contact angle may be

as much as 50° larger than the receding one [Adamson, 1967].

13

There are some causes of contact angle hysteresis. One of them is the liquid or

solid contamination. The scientists studied with graphite and they found that

cleaning can prevent the hysteresis [Fowkes 1964, Harkins, 1922].

Surface roughness is another effect of hysteresis. Johnson and Dettre studied

surface roughness for water on a polytetrafluoroethylene wax and from their

experiments they found the given equation [Finch, Smith, 1979].

cosθr = r.cosθe [19]

where θr is the contact angle observed on a surface roughness r, θe is the

equilibrium contact angle, and r is the ratio of real surface area to the area

assuming a smooth surface.

There are some scientists who studied the roughness effect on the contact angle.

Oliver and Mason studied microspreading on rough surfaces by scanning electron

microscopy, Cox also made equilibrium configurations during liquid spreading

over periodic and randomly surfaces [Osipow, 1962].

Surface heterogeneity is the other effect for hysteresis . Cassie and Baxter studied

for the effect of surface heterogeneity and they found an equation which was

obtained from Wenzel equation:

2211 coscoscos θθθ ffh += [20]

14

where

θh is the thermodynamic equivalent of θ for a heterogeneous surface.

1f and are the respective fractional surface area of region 1 and 2. 2f

θ1 is the contact angle in region 1.

θ2 is the contact angle in region 2.

The local contact angle will depend on the surface energy of the region with

which liquid is in contact [Finch, Smith, 1979].

2.4 The theory of the proposed method of contact angle measurement

The pressure required to prevent a liquid from penetrating a single capillary tube

of radius r, or that required to drain the capillary , is given by the Laplace

equation:

∆P = r

LA θγ cos2 [21]

where γLA is the liquid surface tension, and θ is the solid-liquid contact angle.

Using the Laplace equation for packed particle beds requires a properly chosen

equivalent radius. Kozeny assumed that the pore space of packed beds could be

regarded as equivalent to a bundle of parallel capillaries with a common

equivalent radius, and with a cross-sectional shape representative of the average

shape of the pore cross section. The equivalent radius, re, for a packed bed was

formulated as [Allen, 1977]:

15

re = 2 × solidsof area surface

voidsof volume = 2× VSe

e)1(

− [22]

where e is the packed ped porosity (volume fraction of voids), and SV is the

volume specific surface area of solids, which may be related to an equivalent

diameter, dp, or irregularly shaped particles of the particle bed by the equation

VS = p

SV

d

α [23]

where αSV is the ratio of surface to volume shape factor of particles and is

specific to definition of the equivalent diameter (sieve diameter, surface diameter,

volume diameter, etc). Furthermore, one has to allow for random orientation of

capillaries in a packed bed by introducing a correction factor c [Heertjes and

Kossen, 1967]. The Laplace equation for the capillary pressure of a packed bed

then takes the form.

∆P = k Pde

e

.

)1( − θγ cosLA [24]

where the entry pressure coefficient k is 2αSV /c. This form of the Laplace

equation has been used as means of studying the moisture-retention

characteristics of porous masses. For example, attemps have been made to

correlate the lowest pressure drop, or the so-called entry pressure, required to

dewater an initially saturated filter cake [Wakeman, 1976; Puttock et al.,1986;

Hosten and Sastry, 1989; Condie et al.,1996; Besra et al.,200; Hosten and San,

2002]

16

For a filter cake of unknown entry pressure coefficient k, it is appropriate to

correlate the residual saturation of the cake in its funicular drainage state against

the group of terms on the left side of the following rearranged form of Eq (24).

LA

P

e

Pde

γ)1(

.

−

∆= θcos.k [25]

Plots of residual cake saturation versus the adjusted pressure on the left-hand side

of the above equation yield straight lines for residual saturations between 1.0 and

0.60 of vacuum-dewatered filter cakes [Hosten and Sastry, 1989; Hosten and San,

2002]. This cake saturation range corresponds to the funicular state of the filter

cake in which the liquid front recedes to its equilibrium capillary drain height

without any air breakthrough. By definition of the entry pressure in Eq (24), the

value of the adjusted pressure corresponding to the intercept of the linear portion

of the plots with the full saturation line should yield the coefficient k for the cake,

provided that a perfectly wetting probe liquid (cosθ = 1) is used. Having

determined the value of k, cake drainage tests may be repeated with partially

wetting liquids or surfactant solutions of interest on equivalent powders to

determine apparent contact angles by comparing full-saturation intercepts of the

linear plots.

17

CHAPTER 3

EXPERIMENTAL MATERIAL AND METHODS

3.1 Preparation of Samples

The samples of zircon (ZrSiO4) and rutile (TiO2) which were used in this research

were obtained from DuPont Starke, Florida Operations. The zircon sample

contained 67.22 % ZrO2 , 31.11 % SiO2, 0.11 % TiO2. The rutile sample

contained 96.66 % TiO2, 0.48 % SiO2, 0.39 % ZrO2 and 0.32 % Fe2O3.

Zircon and rutile samples were prepared for experiments by reducing the size in a

porcelain mortar to avoid iron contamination. After reducing the sizes, zircon and

rutile samples dry screened to yield 150x200 mesh for capillaric dewatering,

column wicking and microflotation experiments.

Zircon and rutile samples were purified with dry magnetic separator to eliminate

the iron impurities. After purifying with magnetic separator, the samples cleaned

by rinsing in warm HNO3. Nitric acid ensured to remove the other powders and

cleaned the rutile, zircon samples. The rutile, zircon samples which were treated

with warm nitric acid were washed with distilled water several times until the

samples were completely purified from HNO3. Samples were dried in an oven

with 50° C temperature after cleaning procedure. The zircon and rutile samples

are known to have iso-electric points at pH 4.4 and pH 3.5, respectively.

18

All the materials (crucible, rod, glasses, etc.) which were used for experiments

were cleaned with hot chromic acid, then washed with distilled water until the

green colour of chromic acid disappeared.

3.2 Reagents

Dodecyl amine (CH3(CH2)11NH2), sodium dodecyl sulfate (C12H25SO4Na),

methanol and distilled water were used in capillaric dewatering, column wicking

and microflotation experiments. HCl and NaOH were used as pH regulators.

Dodecyl amine was used as a non-wetting agent in the experiments. An amount

of dodecyl amine which would be used for stock solution was taken and heated

in a pH 4.5-5 solution (distilled water and HCl) to dissolve dodecyl amine and

make the solution homogeneous, then 10-1 M stock solution was prepared. The

required concentrations were prepared from the stock solution.

Sodium dodecyl sulfate was used as another non-wetting chemical in the

experiments. 10-1 M stock solution was prepared from dry powder of the chemical

and the required concentrations were prepared from the stock solutions.

3.3 Experimental Procedure and Methods

3.3.1 Dewatering of filter cakes

Dewatering experiments were conducted in a glass filter crucible of 50 ml

capacity, the bottom of which consisted of a sintered disc of 40-mm diameter and

a porosity index No. 4. Following the cleaning procedure, 50 g of dry particulate

sample was put in the crucible and the crucible was filled with liquid until the

19

level of the liquid was enough to mix the sample with liquid. The sample was

mixed with liquid (water, surfactant solution or methanol) by the help of a glass,

stirring rod to form a slurry. The crucible was then securely fitted to a vacuum

flask by means of a rubber stopper and the thoroughly mixed slurry was allowed

to drain by gravity, or by applying a slight vacuum, forming a fully saturated

filter cake on the sintered disc (Figure 3.1). At this moment, the crucible was

removed from the flask and quickly weighed on an electronic balance without

disturbing the filter cake. Any excess liquid remaining on the bottom of the

crucible or the porous disc was wiped off before the weighing process.

Immediately after the weighing the crucible was placed back on the vacuum flask

and a small vacuum (0.5 in Hg) was applied to dewater the filter cake to its

residual saturation level, which generally took around two minutes of dewatering

time. The vacuum was then shut off, the crucible was removed and quickly

weighed, and placed back on the vacuum system. The vacuum level was

incremented by another 0.5 in Hg and the cake was again dewatered to it new

residual saturation level and then weighed. This procedure was repeated several

times to obtain residual saturation data at various vacuum levels within the

capillaric (or funicular) dewatering regime.

3.3.2 Column Wicking

Column wicking experiments were conducted in a clear plastic tube of 10 cm

height and 2 mm width, the bottom of which was closed with a fritted disc. The

dried powder was packed into the tube by tapping. The tube was then placed

vertically so that the bottom of the tube was just in contact with the liquid. The

rise of the liquid up the packed bed of particles was measured as a function of

time.

20

Figure 3.1. The illustration of capillaric dewatering experiments

Figure 3.2. The illustration of column wicking experiments

21

3.3.3 Microflotation Experiments

The microflotation experiments were performed with a Hallimond tube using

nitrogen gas. One gram of dry powder sample was used in each test. The powder

in the tube was conditioned for 10 minutes with the prepared solutions by mixing

with a magnetic stirrer. After conditioning, nitrogen gas was allowed to flow

through the fritted disc at the bottom of the tube to generate air bubbles. After 5

minutes of flotation time, the nitrogen switch was turned off, and the particles in

the float and sink fractions were collected separately and dried in an oven at 60°C

to calculate the weight recovery of the floated particles. A schematic drawing of

the microflotation system is given in Figure 3.3.

Figure 3.3 The illustration of Hallimond tube.[Muratoğlu, 2000]

22

CHAPTER 4

EXPERIMENTAL RESULTS AND DISCUSSION

In this chapter the results of capillaric dewatering experiments, column wicking

experiments and microflotation experiments are given and compared by the help

of figures.

4.1 Capillaric dewatering experiments

First the capillaric dewatering experiments were performed with methanol (the

completely wetting liquid), water and water-methanol mixtures for zircon and

rutile samples.

4.1.1 Experiments with zircon

It is shown in Figure 4.1 that, from the capillaric dewatering experiments by

using methanol, we can find the value of k.cosθ = 8.00. It is known that methanol

is a completely wetting liquid and therefore θ = 0. Hence,

k.cosθ = 8.00, θ = 0 ⇒ k = 8.00

23

This k value for the zircon sample will be used in all calculations in the rest of the

thesis. The contact angle of zircon with water can then be found from the

equation

k.cosθ = 6.02 ⇒ 8.00. cosθ = 6.02 ⇒ θ = 41.19° for water

F

igure 4.1 Residual cake saturation versus k.cosθ plots for -150 + 200 mesh zircon

when water or methanol was used as the liquid.

6.02 8.00

Zircon - WaterZircon - Methanol

1.000

Satu

ratio

n 0.800

0.600

0.400

0.200

0.0000.00 5.00 10.00 15.00

k.cosθ

Figures 4.2 through 4.7 show the experimental results obtained with the cake

dewatering of zircon samples when various mixtures of water and methanol were

used as the medium liquid. The purpose of these experiments was to find critical

(k.cosθ) values from which the contact angle values could be obtained for the

liquids of varying surface tension.

24

6.18

1.000

0.800Sa

tura

tion

Zircon-10% Methanol0.600

Zircon- Methanol0.400

0.200

0.0000.00 5.00 10.00 15.00

k cos θ

Figure 4.2 Residual cake saturation versus k.cosθ plots for -150 + 200 mesh

zircon when methanol or a water-methanol mixture was used as the liquid.

6.16

Zircon - MethanolZircon-25% Methanol

1.000

0.800

Satu

ratio

n

0.600

0.400

0.200

0.0000.00 5.00 10.00 15.00

k cosθ



25

6.55

1.0000.800

Satu

ratio

n

Zircon-40% Methanol0.600

Zircon - Methanol0.4000.2000.000

0.00 5.00 10.00 15.00

k cosθ



6.75


1.0000.800

Satu

ratio

n 0.6000.4000.2000.000

0.00 5.00 10.00 15.00

k cosθ



26

7.56

1.0000.800

Satu

ratio

n

Zircon - Methanol0.600

Zircon-65% Methanol0.4000.2000.000

0.00 5.00 10.00 15.00

k cosθ



7.50

1.0000.800


Satu

ratio

n 0.6000.4000.2000.000

0.00 5.00 10.00 15.00

k cosθ



27

Knowing the previously found k = 8.0 value for the zircon filter cakes, we can

calculate the contact angle values from the k.cosθ values obtained from the

figures for the cases where we have different liquid surface tensions resulting

from using varying amounts of methanol in mixture with water. Table 4.1 and

Figure 4.8 present the contact angle values found by this procedure.

Table 4.1 The contact angle and k.cosθ values for the zircon sample as obtained

from cake dewatering tests using water-methanol mixtures.

Methanol

% in water

100 80 65 50 40 25 10 0

k.cosθ 8.00 7.50 7.56 6.75 6.55 6.16 6.18 6.02

Contact angle, ° 0 20.36 19.09 32.46 35.04 39.64 39.42 41.19

05

1015202530354045

0 20 40 60 80 100 120

Methanol, %

θ

Figure 4.8 Contact angle values obtained with zircon by using methanol-water

mixtures.

28

These results give us an idea that the capillaric dewatering method can be an

applicable method for contact angle measurements because we know that

methanol is a completely wetting liquid and always gives zero contact angle with

all minerals. When the proportion of methanol in the mixture increases, the

surface tension of the contacting liquid decreases, and, therefore, the contact

angle of the methanol-water mixture on the zircon particle surfaces decreases.

Having proven the applicability of the new method with methanol, similar tests

were conducted with a surfactant, dodecyl amine (DA), which is a common

flotation collector. Figures 4.9 and 4.10 show the contact angles of zircon, as a

function of pH when 10-5 M dodecylamine solutions were used as the liquid in

cake dewatering tests. The k.cosθ values obtained from the point where the sharp

decrease of saturation occurred and the known value of k = 8.0 for the zircon

filter cakes were again used to calculate the contact angle values. Table 4.2 and

Figure 4.10 summarize the results obtained as such.

5.28 6.01 6.21

pH 10pH 6pH 4

0.000

0.00

1.000

0.8000.600

0.4000.200

Satu

ratio

n

2.00 4.00 6.00 8.00 10.00

k.cosθ


zircon when 10-5M dodecylamine solution was used as the liquid.

29

Table 4.2. The contact angle and k.cosθ values from the cake dewatering experiments with -150+200 mesh zircon by using 10-5 M dodecylamine at various pH values of the solution. pH 4 6 8 10 Contact angle, θ° 41.30 48.70 49.74 39.8 k.cosθ 6.01 5.28 5.17 6.21

55.0050.0045.00θ

40.0035.0030.00

0 2 6 8 10 12 4

pH

Figure 4.10 The contact angle values for the -150+200 mesh zircon sample in

contact with 10-5M dodecylamine solutions at various pH values.

It is obvious from the contact angle values that the highest hydrophobicity was

obtained in a pH range 6 to 8. This must be the range where maximum adsorption

of cationic dodecylamine ions occurred on negatively charged zircon surfaces, the

iso-electric point of which was known to be pH 4.4.

Similar dewatering experiments were also performed with zircon by using

5.10-5 M dodecylamine solutions at different pH values, and the results obtained

were almost identical with those obtained by using 10-5 M dodecyl amine.

Therefore, figures and the contact angle values pertinent to the experiments with

10-5 M dodecyl amine solutions were not included here in the text to avoid

30

repetition, but the data can be found in the appendix. The contact angle

measurements could not performed with 10-4 M dodecylamine because of particle

aggregation problems at such a high concentration of the surfactant.

Another common surfactant, but of anionic type, namely, sodium dodecyl sulfate

(SDS), was also tested for generating zircon surfaces with different degrees of

hydrophobicity. Figure 4.11 presents the experimental results from the

dewatering of filter cakes of zircon particles treated with sodium dodecyl sulfate

at various pH values. This surfactant is known to adsorb on the silicate or oxide

mineral surfaces dominantly by electrostatic interaction; therefore, no effect on

the contact angle was observed at pH values of 4, 6, and 8 as the zircon particle

surfaces are either neutral or negatively charged at these pH values (i.e.p. is

around pH4.4). On the other hand, the surfaces are positively charged at pH 2,

and the anionic SDS can adsorb on the surfaces and make them more

hydrophobic. The measured contact angles with SDS at pH 2 were 49.6°, 52°, and

53.2° for 10-5 M, 5x10-5 M, and 10-4 M solutions, respectively. It is obvious that an

order of magnitude increase in SDS concentration beyond 10-5M can cause only a

slight increase in the contact angle.

31

4.79

0.0000.2000.4000.6000.8001.000

Satu

ratio

n

pH 8pH 6pH 4pH 2

0.00 2.00 4.00 6.00 8.00 10.00

k.cosθ


zircon when 10-4 M sodium dodecyl sulfate solution was used as the liquid.

4.1.2 Experiments with Rutile

It is shown in Figure 4.12 that, from the capillaric dewatering experiments by

using the completely wetting (θ = 0°) liquid methanol, we can find the value of k

as 8.64. This value is again a fixed reference for all the other experiments

preformed with the rutile sample. Referring the k.cosθ = 7.26 value and knowing

the k value, we can calculate that the contact angle between rutile and water is

32.83° which is almost 10° lower than that found for zircon.

Figures 4-13 through 4.18 present the residual cake saturation versus k.cosθ plots

for the rutile sample treated with water-methanol mixtures of varying methanol

proportions to change the surface tension of the mixture liquid. Figure 4-19

shows the surface tension of the water-methanol mixtures.

32

Table 4.3 summarizes the information derived from the figures. Again, the

contact angle increases with the increase in the liquid surface tension, or with the

decrease in the proportion of methanol in the mixture. It is obvious that water is a

partially-wetting liquid for rutile as well as zircon, because we observe finite

contact angles with the use of water as the liquid in dewatering experiments.

7.26 8.64

Rutile - WaterRutile - Methanol

1.0000.800

Satu

ratio

n

0.6000.4000.2000.000

0.00 5.00 10.00 15.00

k.cosθ


rutile when water or methanol was used as the liquid.

7.91

1.000

Satu

ratio

n 0.800Rutile-10% Methanol

0.600Rutile - Methanol

0.400

0.200

0.0000.00 5.00 10.00 15.00

k.cosθ


rutile when methanol or a water-methanol mixture was used as the liquid.

33

8.04

1.000

0.800Sa

tura

tion

Rutile-25% Methanol0.600

Rutile - Methanol0.400

0.200

0.0000.00 5.00 10.00 15.00

k.cosθ



7.81

Rutile-40% MethanolRutile - Methanol

0.000

5.000.00

1.000

0.800

0.600

0.400

0.200

Satu

ratio

n

10.00 15.00

k.cosθ



34





8.05

0.000

1.200

1.000

0.800Sa

tura

tion

Rutile-50% Methanol0.600

Rutile - Methanol0.400

0.200

0.00 5.00 10.00 15.00

k.cosθ

8.25


0.000

5.000.00

1.200

1.000

0.800

0.600

0.400

0.200

Satu

ratio

n

10.00 15.00

k.cosθ

35

8.29


0.000

5.000.00

1.200

1.000

0.800

0.600

0.400

0.200

Satu

ratio

n

10.00 15.00

k.cosθ



00.010.020.030.040.050.060.070.08

0 20 40 60 80 100 120

Methanol, %

Surfa

ce te

nsio

n, N

/M

Figure 4.19 Surface tension values of methanol mixtures.

36

Table 4.3 The contact angle and k.cosθ values for the rutile sample as obtained

from cake dewatering tests using water-methanol mixtures.

Methanol Contact Angle k.cosθ

% θ

100 0 8.64

80 16.36 8.29

65 17.28 8.25

50 21.29 8.05

40 25.31 7.81

25 21.47 8.04

10 23.72 7.91

0 32.83 7.26

Cake dewatering experiments using dodecyl amine and sodium dodecyl sulfate

solutions at various pH values were also conducted with the rutile sample. The

data obtained were again plotted as saturation-versus-k.cosθ graphs, critical

points on the plots were found, and the contact angles were calculated. Table 4.4

summarizes the results.

Dodecyl amine is again most effective at around pH 6 in increasing the contact

angle, but the angle is almost 10° smaller than the maximum angle obtained in

the case of zircon-dodecyl amine system. Sodium dodecyl sulfate was again

effective only at pH 2 where the rutile surface is positively charged and led to

more or less the same contact angles (54°) as the zircon-sodium dodecyl sulfate

system at the optimal addition of the surfactant (10-4M).

37

Table 4.4 Contact angles for rutile obtained from dewatering experiments using

dodecyl amine and sodium dodecyl sulfate solutions at various pH values.

Concentration pH Contact Angle

4 35.31

10-5 M DA 6 37.22 8 35.66 10 33.19 4 35.43

5.10-5 M DA 6 38.41 8 35.99 10 32.71 4 39.04

10-4 M DA 6 40.91 8 41.71 10 33.79

10-4 M SDS 2 54.96 5.10-5 M SDS 2 53.32 10-5 M SDS 2 40.19

Distilled Water 5.5 32.83

4.2 Column Wicking Experiments

Column wicking experiments were performed to compare the contact angle

values obtained from capillaric dewatering experiments. However, one must keep

in mind that the column wicking method measures the advancing contact angle

and the new method proposed in this thesis measures the receding contact angle.

As we have already pointed out that the advancing contact angle may be as much

as 50° larger than the receding contact angle.

38

Figure 4.20 shows the plots obtained from the column wicking experiments with

the zircon sample when methanol, hexane, formamide, and water are individually

used as the liquid. Coinciding plots of methanol, hexane, and formamide justify

that the methanol is, in fact, a completely-wetting liquid since it is known from

the pertinent literature that hexane has been used as a completely-wetting liquid.

The quantity A in the vertical axis of the figure is given by

A = ⎟⎟⎠

⎞⎜⎜⎝

⎛

L

h

γ

η..2 2

[26]

so that the slope of the linear plot is equal to R.cosθ, where R is the effective

interstitial pore radius between the packed particles in the column. Since cosθ = 1

for a completely-wetting liquid, the value of R for a certain packed bed of

particles can be directly calculated from the slope of the plot of the completely-

wetting liquid. Knowing the value of R, the contact angle for a partially-wetting

liquid may be found agin by the slope of its linear plot. For example, from the

column wicking plot of methanol-zircon system R = 0.02405, and for the water-

zircon system

R.cosθ = 0.00826

0.02405. cosθ = 0.00687 ⇒ θ = 69.91°

This is the advancing contact angle for water-zircon system and, as expected, it is

greater than the receding contact angle (41.19°) obtained by the cake dewatering

method by almost a difference of 29°.

A similar set of column wicking plots are given for rutile in Figure 4.21, from

which it can be calculated that the advancing contact angle for water-rutile system

is 63.55° which is approximately 30° greater than the receding contact angle

found by the dewatering method. The resemblence with the zircon-water system

is quite striking.

39

0

0.5

1

1.5

2

2.5

3

3.5

4

0 50 100 150 200

seconds

AZircon - WaterZircon - MethanolZircon - HexaneZircon -Formamide

Figure 4.20 Column wicking plots for -150+200 mesh zircon particles with

completely-wetting organic liquids and partially-wetting liquid water.

0

0.5

1

1.5

2

2.5

3

3.5

4

0 100 200 300

Seconds

A

Rutil-HexaneRutil-MethanolRutil-Water

Figure 4.21 Column wicking plots for -150+200 mesh rutile particles with

completely-wetting organic liquids and partially-wetting liquid water.

40

Figures 4.22 and 4.23 show the column wicking plots for zircon and rutile,

respectively, with the use of water-methanol mixtures. The receding contact

angles derived from these figures are presented in Table 4.5 and Table 4.6.

0

0.5

1

1.5

2

2.5

0 50 100 150

seconds

A

Zircon - % 10 MZircon - % 25 MZircon - % 40 MZircon - % 50 MZircon - % 65 MZircon - % 80 MZircon - MZircon - Water

Figure 4.22 Column wicking plots for -150+200 mesh zircon particles with water-methanol mixtures.

0

0.2

0.4

0.6

0.8

1

1.2

1.4

1.6

0 50 100 150

seconds

A

% 10 Methanol% 25 Methanol%40 Methanol% 50 Methanol% 65 Methanol% 80 Methanol

Figure 4.23 Column wicking plots for -150+200 mesh rutile particles with water-methanol mixtures.

41

Table 4.5 The advancing and receding contact angles of zircon with water-methanol mixtures in the column wicking experiments.

Liquid θA θR θA – θR

Water 69.91 41.19 28.72 10% Methanol 69.49 39.42 30.07 25% Methanol 65.32 39.64 25.68 40% Methanol 66.91 35.04 31.87 50 % Methanol 60.66 32.46 28.2 65% Methanol 52.92 19.09 33.83 80 % Methanol 51.32 20.36 30.96 Methanol 0 0 0

Table 4.6 The advancing and receding contact angles of rutile with water-

methanol mixtures in the column wicking experiments.

Liquid θA θR θA – θR

Water 63.55 32.83 30.72 10% Methanol 62.14 23.72 38.42 25% Methanol 61.99 21.47 40.72 40% Methanol 59.10 25.31 33.79 50 % Methanol 56.46 21.29 35.17 65% Methanol 45.95 17.28 28.67 80 % Methanol 34.94 16.36 18.58 Methanol 0 0 0

We can see from the tables that there is a difference of 20° to 40° between the

advancing contact angles obtained from column wicking experiments and the

receding contact angles obtained from cake dewatering experiments.

Column wicking experiments were also conducted with dodecyl amine and

sodium dodecyl sulfate solutions to make a comparison with the cake dewatering

experiments, and the results are presented in Figures 4.24-4.30 and Tables 4.7 and

4.8

42

1.2

1

0.810-5 M - pH 4 10-5 M - pH 6 10-5 M - pH 8 10-5 M - pH 10

A0.6

0.4

0.2

00 50 100 150

seconds


10-5 M dodecyl amine at different pH values.

1.2

1

0.85.10-5 M - pH 4 5.10-5 M - pH6 A

0.65.10-5 M - pH 8 5.10-5 M - pH 10

0.4

0.2

00 50 100 150

seconds


5.10-5 M dodecyl amine at different pH values

43

0.8

0.7

0.6

0.5

5.10-5 M - pH210-4 M SDS- pH 2

10-5 MA0.4

0.3

0.2

0.1

00 50 100 150

seconds


different concentrations of sodium dodecyl sulfate at pH 2.

Table 4.7 The advancing and receding contact angles of zircon from column

wicking (θA) and cake dewatering experiments (θR).

Liquid pH θA θR θA – θR 10-5 M DA 4 72.13 41.3 30.83 6 80.7 48.7 32 8 82.07 49.74 32.33 10 67.85 39.08 28.77 5.10-5 M DA 4 79.6 42.48 37.12 6 82.5 49.83 32.67 8 84.7 51.31 33.39 10 69.33 39.98 29.35 10-4 M SDS 2 81.06 53.22 27.84 5.10-5 M SDS 2 75.49 51.95 23.54 10-5 M SDS 2 71.52 49.64 21.88

44

0

0.1

0.2

0.3

0.4

0.5

0.6

0 20 40 60 80 100

seconds

A

pH4pH6pH8pH10

Figure 4.27 Column wicking plots for -150+200 mesh rutile particles with 10-5 M

dodecyl amine at different pH values.

0

0.1

0.2

0.3

0.4

0.5

0.6

0 20 40 60 80 100

t

A

pH4pH6pH8pH10


5x10-5 M dodecyl amine at different pH values.

45

0

0.1

0.2

0.3

0.4

0.5

0.6

0 50 100 150

seconds

A

pH4pH6pH8pH10

Figure 4.29 Column wicking plots for -150+200 mesh rutile particles with 10-4 M

dodecyl amine at different pH values.

0.05

.10

0.15

.20

0.25

.30

0.35

.40

0.45

0.5

pH2 - 10-4 M SDS

pH2 - 5.10-5 M SDS

pH2 - 10-5 M SDS

A

00 50 100 150

seconds


different concentrations of sodium dodecyl sulfate at pH 2.

46

Table 4.8 The advancing and receding contact angles of rutile from column

wicking (θA) and cake dewatering experiments (θR).

Liquid pH θA θR θA – θR 10-5 M DA 4 65.37 35.31 30.06 6 78.42 37.22 41.2 8 73.57 35.66 37.91 10 63.25 33.19 30.06 5.10-5 M DA 4 72.11 35.43 36.68 6 80.19 38.41 41.78 8 77.19 35.99 41.2 10 63.02 32.71 30.31 10-4 M SDS 4 74.39 39.04 35.35 6 83.07 40.91 42.16 8 79.08 41.71 37.37 10 63.48 33.79 29.69 10-4 M SDS 2 77.97 54.96 23.01 5.10-5 M SDS 2 76.84 53.32 23.52 10-5 M SDS 2 75.52 40.19 35.33

When the receding and advancing contact angles given in Table 4.7 and Table 4.8

are compared, we may see that there are differences between advancing and

receding contact angles. There is an agreement between the results of column

wicking and cake dewatering experiments. At pH 8, in all concentrations of

dodecyl amine, both receding and advancing contact angles gave a higher degree.

In the experiments with sodium dodecyl sulfate, we can see that, at pH 2, the

degree of contact angle is getting higher with the increase of collector and also

47

the receding contact angles are parallel to advancing contact angles from the

column wicking experiments.

4.3 Microflotation Experiments

Microflotation experiments were performed whether the contact angles obtained

from cake dewatering experiments are reliable and correlate well with the

flotation behavior of the zircon and rutile particles. Figure 4.31-4.34 present the

flotation recoveries obtained at various conditions which were also tested in

contact angle measurement experiments.

100

Flot

atio

n R

ecov

ery

, %

90

80

10-5 M10-5 M R

5.10-5M R5.10-5 M

10-4M10-4M R

10-3M10-3M R70

60

50

4030

20

10

00 2 4 6 8 10 12

pH

Figure 4.31 Flotation response of -150+200 mesh zircon with dodecyl amine at

different pH values. R denotes repeat experiments.

48

10090 10-3 M SDS

Flot

atio

n re

cove

ry %

80

10-3 M SDS - R70

10-4 M SDS60

10-4 M SDS - R50

5.10-5 M SDS40

5.10-5 M SDS - R10

30 -5 M SDS2010-5 M SDS - R10

00 2 4 6 8 10

pH

Figure 4.32 Flotation response of -150+200 mesh zircon with sodium dodecyl

sulfate at different pH values. R denotes repeat experiments.

100

90

Flot

atio

n R

ecov

ery

, %

80 10-3M10-3M R10-4M10-4M R5.10-5 M5.10-5M R10-5 M10-5 M R

70605040302010

00 2 4 6 8 10 12

pH

Figure 4.33 Flotation response of -150+200 mesh rutile with dodecyl amine at

different pH values. R denotes repeat experiments.

49

10090

Flot

atio

n re

cove

ry, %

10-5 M SDS5.10-5 M SDS - R

5.10-5 M SDS5.10-5 M SDS - R

10-4 M SDS10-4 M SDS - R

10-3 M SDS10-3 M SDS - R

80

70

60

50

40

30

20

10

00 2 4 6 8 10

pH

Figure 4.34 Flotation response of -150+200 mesh rutile with sodium dodecyl

sulfate at different pH values. R denotes repeat experiments.

It can be seen from the figures that the flotation recovery of minerals are

consistent with the contanct angles obtained from the proposed method of

measurement in the sense that maximum flotation recovery ranges are in very

good agreement with maximum contact angle ranges where we expect highest

degrees of hydrophobicity, and, hence, maximum floatability. The only difference

between the microflotation tests and capillaric dewatering tests is the amount of

collector which adsorbed by the solid, in microflotation 1 gr of solid was used

while in dewatering 50 gr of solid was used. This is the reason of high percent of

flotation.

50

These results suggest that, instead of carrying out tedious microflotation tests

requiring special experimental set-ups, we may conduct simple and fast filtration

experiments to study the wetting characteristics of solid particulates treated with

various chemicals. Furthermore, the proposed method of measurement yields the

receding contact angles, which represent the true physical event taking place in

froth flotation in which air replaces water at already wetted surfaces.

51

CHAPTER 5

CONCLUSIONS

In this research, the determination of the contact angle by capillaric dewatering of

filter cakes was studied on zircon and rutile powders and the findings are

compared with column wicking and microflotation experiments. As a result of

this study, the following conclusions can be drawn:

- Capillaric dewatering method can be used for determining the receding

contact angle of powders. Capillaric dewatering method is an easily applicable

technique to determine the contact angles of powders and also for determining the

contact angles for flotation applications.

- Comparing column wicking experiments and capillaric dewatering

experiments, it is observed that the maximum contact angle range for zircon by

using dodecyl amine is from pH 6 to pH 8, and by using sodium dodecyl sulfate it

is below pH 3,and comparing the column wicking experiments and capillaric

dewatering experiments, it is observed that the maximum contact angle range for

rutile by using dodecyl amine is from pH 6 to pH 8, and by using sodium dodecyl

sulfate is below 3.

- The difference between advancing and receding contact angles can be

higher than 40°.

52

- Zircon gives a higher contact angle than rutile for the systems studied.

- Highly acidic and highly alkaline conditions are not suitable for flotation

of zircon and rutile by using dodecyl amine, as verified by the very low value of

the contact angle at these conditions.

53

REFERENCES

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54

8. Douillard J.M., Zajac J., Malandrini H., et al., Contact angle and film pressure:

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12. Good R.J., Mittal K.L., Contact Angle, Wettability and Adhesion,

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2665ff.

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liquid systems, Powder Technology, Volume 1, Issue 1, February 1967, Pages 33-

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15. Hoşten, Ç., Micro-floatability of rutile and zircon with soap and amine type

collectors, Physicochemical Problems of Mineral Processing, Volume 35, 2001,

Pages 161-170

16. Hoşten Ç., Sastry K.V.S., Empirical correlations for the prediction of cake

dewatering characteristics, Minerals Engineering, Volume 2, Issue 1, 1989,

Pages 111-119

17. Iveson S.M., Holt S., Biggs S., Contact angle measurements of iron ore

powders, Colloids and Surfaces, Volume 166, 2000, Pages 203-214

18. Krajewski S.R., Kujawski W., Dijioux F., et al., Grafting of ZrO2 powder and

ZrO2 membrane by fluoroalkylsilane, Colloids and Surfaces A: Physicochemical

and Engineering Aspects, Volume 243, Issues 1-3, August 2004, Pages 43-47

19. Muratoğlu R.A., Floatability and adsorption characteristics of zircon with

sodium oleate, Ankara, Metu, 2000

20. Osipow L.I., Surface Chemistry, Theory and Industrial Applications,

Reinfold Pub. Corp., New York, 1962

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dewatering of alumina trihydrate — The role of cake porosity and interfacial

phenomena, International Journal of Mineral Processing, Volume 17, Issues 3-4,

July 1986, Pages 205-224

56

22. Rondeau X., Affolter C., Kommunjer L., et al., Experimental determination of

capillary forces by crushing strength measurements, Powder Technology,

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Capillary Rise Phenomena, Colloids and Surfaces, Volume 161, 2000, Pages 81-

87

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from a high-silica glaze, Minerals Engineering, Volume 15, Issue 7, July 2002,

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filter cakes, International Journal of Mineral Processing, Volume 3, Issue 3,

September 1976, Pages 193-206

57

APPENDIX A

TABLES OF CAPILLARIC DEWATERING EXPERIMENTS

Table A 1. -100+200 mesh quartz experimented with methanol

TEST NO TEST TEST SIZE DRY SOLIDS CAKE POROSITYSOLIDS LIQUID (MESH) (GRAM)

1 Quartz 100% .-100+200 30 0,53Methanol

Vacuum 0,2 0,2 0,6 1 1,5 2 2,5 3(inch-Hg)Dewat. 0 2 2 2 2 2 2 2Time(min)Liquid 10,23 10,18 10,09 10,01 9,93 8,71 5,84 4,76(Gram)Res Mois 25,42 25,33 25,16 25,01 24,86 22,50 16,3 13,69

%Saturation 1 0,995 0,986 0,978 0,970 0,85 0,570 0,465

Table A.2. -100+200 mesh quartz experimented with water


2 Quartz Water .-100+200 30,02 0,47

Vacuum 1 1 1,5 2 2,5 3 3,5 4(inch-Hg)Dewat. 0 3 3 3 3 3 3 3Time(min)Cake 39,91 39,88 39,86 39,7 39,68 38,7 36,2 34(Gram)Res Mois 24,78 24,72 24,68 24,38 24,34 22,36 17 11,7

%Saturation 1 0,997 0,994 0,978 0,976 0,87 0,619 0,402

58

Table A.3. -100+200 mesh quartz experimented with 80% methanol


3 Quartz 80% .-100+200 30 0,47Methanol

Vacuum 0,5 0,5 1 1,5 2 2,5 3 3,5(inch-Hg)Dewat. 0 2 2 2 2 2 2 2Time(min)Liquid 8,51 8,47 8,42 7,71 5,08 4,41 3,91 3,47(Gram)Res Mois 22,09 22,01 21,91 20,44 14,48 12,8 11,5 10,36

%Saturation 1 0,995 0,989 0,905 0,596 0,52 0,46 0,407



4 Quartz 65% .-100+200 30 0,45Methanol

Vacuum 0,5 0,5 1 1,5 2 2,5 3 3,5(inch-Hg)Dewat. 0 2 2 2 2 2 2 2Time(min)Liquid 8,06 7,77 7,66 7,02 5,31 4,47 4,02 3,58(Gram)Res Mois 21,17 20,57 20,33 18,96 15,03 13 11,8 10,66

%Saturation 1 0,964 0,95 0,87 0,658 0,55 0,5 0,444

59



5 Quartz 50% .-100+200 30 0,45Methanol


%Saturation 1 0,993 0,99 0,986 0,956 0,82 0,61 0,487



6 Quartz 40% .-100+200 30 0,48Methanol


%Saturation 1 0,996 0,992 0,99 0,919 0,75 0,6 0,545

60



7 Quartz 25% .-100+200 30 0,48Methanol


%Saturation 1 0,997 0,989 0,985 0,982 0,89 0,7 0,6



8 Quartz 10% .-100+200 30 0,47Methanol


%Saturation 1 0,998 0,995 0,993 0,992 0,98 0,8 0,598

61


TEST NO TEST TEST SIZE DRY SOLIDSCAKESOLIDS LIQUID MESH GRAM POROSITY

9 Quartz Water .-100+200 20 0,463Vacuum 1 1 1,5 2 2,5 3 3,5 4(inch-Hg)Dewat. 0 5 5 5 5 5 5 5TimeWet Cake 26,8 26,51 26,5 26,48 26,47 25,3 22,9 22,52GramRes Mois 24,64 24,55 24,52 24,47 24,44 20,9 12,8 11,19

%Saturation 1 0,99 0,99 0,99 0,98 0,8 0,45 0,38



10 Quartz Water .-200+400 30 0,551Vacuum 1 1 1,5 2 2,5 3 3,5 4(inch-Hg)Dewat. 0 6 6 6 6 6 6 6TimeWet Cake 43,96 42,76 42,69 42,67 42,66 42,7 42,6 42,62GramRes Mois 31,75 29,84 29,72 29,69 29,67 29,7 29,6 29,61%Saturation 1 0,91 0,909 0,907 0,906 0,91 0,91 0,904

62

Table A.11. -100+200 mesh quartz experimented with hexane

TEST NO TEST TEST SIZE DRY SOLIDSCAKESOLID LIQUID MESH GRAM POROSITY

11 Quartz Hexane .-100+200 30 0,487Vacuum 1 1 1,5 2 2,5 3(inch-Hg)Dewat. 0 5 5 5 5 5TimeWet Cake 37,13 34,65 33,75 32,69 30,95 30GramRes Mois 19,2 13,42 11,11 8,23 3,07 0,06%Saturation 1 0,651 0,526 0,377 0,133 0



12 Quartz Hexane .-100+200 30 0,479Vacuum 1 1 1,5 2 2,5 3(inch-Hg)Dewat. 0 5 5 5 5 5TimeWet Cake 36,91 34,44 33,64 32,57 30,23 30GramRes Mois 18,72 12,89 10,82 7,89 0,76 0,03%Saturation 1 0,643 0,527 0,372 0,033 0

63



13 Quartz Hexane .-200+400 30 0,51Vacuum 0,2 0,2 0,4 0,6 0,8 1 1,2 1,4(inch-Hg)Dewat. 0 5 5 5 5 5TimeWet Cake 37,88 37,5 37,29 37,08 36,83 36,5 36,2 35,8GramRes Mois 20,8 20 19,55 19,09 18,54 17,9 17,1 16,2%Saturation 1 0,951 0,924 0,897 0,865 0,83 0,78 0,735



14 Quartz Water .-100+200 30 0,53Vacuum 0,1 0,2 0,4 0,6 0,8 1 1,2(inch-Hg)Dewat. 0 2 2 2 2 2 2 2TimeLiquid 8,61 8,4 8,11 7,83 7,53 7,22 5,87 4,53GramRes Mois 22,2 21,8 21,2 20,69 20 19,4 16,4 13,11%Saturation 1 0,975 0,941 0,909 0,874 0,84 0,68 0,526

64

Table A.15. -150+200 mesh zircon experimented with water


15 Zircon Water .-150+200 50 0,462

Vacuum with 0,2 0,5 1 1,5 1,6 1,7 2(inch-Hg) gravityDewat. 0 2 2 2 2 2 2 2Time(min)Cake 59,12 59,09 59,07 59,04 59,03 59 59 55,3(Gram)Res Mois 15,43 15,38 15,35 15,31 15,30 15,30 15,28 9,58

%Saturation 1 0,997 0,995 0,991 0,990 0,990 0,989 0,581

Table A.16. -150+200 mesh zircon experimented with methanol


16 Zircon Methanol .-150+200 50 0,47

Vacuum with 0,2 0,4 0,6 0,7 0,8 1 1,2(inch-Hg) gravityDewat. 0 2 2 2 2 2 2 2Time(min)Cake 57,37 57,31 57,24 57,16 57,15 53,7 53 52,59(Gram)Res Mois 12,85 12,76 12,65 12,53 12,51 6,80 5,57 4,92

%Saturation 1,000 0,992 0,982 0,972 0,970 0,495 0,400 0,351

65

Table A.17. -150+200 mesh zircon experimented with methanol


17 Zircon Methanol .-150+200 50 0,463

Vacuum with 0,2 0,4 0,6 0,7 0,8 1 1,2(inch-Hg) gravityDewat. 0 2 2 2 2 2 2 2Time(min)Cake 57,29 57,28 57,28 57,21 57,19 55 52,9 51,65(Gram)Res Mois 12,72 12,71 12,71 12,60 12,57 9,06 5,41 3,19

%Saturation 1,000 0,999 0,999 0,989 0,986 0,683 0,392 0,226

Table A.18. -150+200 mesh zircon experimented with 10% methanol


18 Zircon Methanol .-150+200 50 0,45510%

Vacuum with 0,5 1 1,2 1,4 1,6 1,8(inch-Hg) gravityDewat. 0 2 2 2 2 2 2Time(min)Cake 58,72 58,64 58,42 58,4 58,28 55,7 54,3(Gram)Res Mois 14,85 14,73 14,41 14,38 14,21 10,15 7,83

%Saturation 1,000 0,991 0,966 0,963 0,950 0,648 0,487

66



19 Zircon Methanol .-150+200 50 0,46110%


%Saturation 1,000 0,999 0,998 0,998 0,998 0,745 0,474



20 Zircon Methanol .-150+200 50 0,46125%


%Saturation 1,000 0,994 0,991 0,990 0,791 0,552 0,420

67



21 Zircon Methanol .-150+200 50 0,45925%


%Saturation 1,000 1,000 0,999 0,997 0,755 0,675 0,377



22 Zircon Methanol .-150+200 50 0,44640%

Vacuum with 0,4 0,6 0,8 1 1,2 1,4(inch-Hg) gravityDewat. 0 2 2 2 2 2 2Time(min)Cake 57,95 57,77 57,69 57,55 57,41 55,1 54(Gram)Res Mois 13,72 13,45 13,33 13,12 12,91 9,27 7,32

%Saturation 1,000 0,977 0,967 0,950 0,932 0,643 0,497

68



23 Zircon Methanol .-150+200 50 0,44340%

Vacuum with 0,4 0,6 0,8 1 1,2 1,4(inch-Hg) gravityDewat. 0 2 2 2 2 2 2Time(min)Cake 57,86 57,85 57,83 57,83 57,82 55,2 52,1(Gram)Res Mois 13,58 13,57 13,54 13,54 13,52 9,47 4,05

%Saturation 1,000 0,999 0,996 0,996 0,995 0,665 0,268



24 Zircon Methanol .-150+200 50 0,43950%

Vacuum with 0,5 1 1,2 1,4(inch-Hg) gravityDewat. 0 2 2 2 2Time(min)Cake 57,61 57,47 57,4 54,9 54,22(Gram)Res Mois 13,21 13,00 12,89 8,93 7,78

%Saturation 1,000 0,982 0,972 0,644 0,555

69



25 Zircon Methanol .-150+200 50 0,44250%

Vacuum with 0,5 1 1,2 1,4(inch-Hg) gravityDewat. 0 2 2 2 2Time(min)Cake 57,68 57,66 57,65 55,23 53,65(Gram)Res Mois 13,31 13,28 13,27 9,47 6,80

%Saturation 1,000 0,997 0,996 0,681 0,475



26 Zircon Methanol .-150+200 50 0,46665%

Vacuum with 0,2 0,4 0,6 0,7 0,8 1(inch-Hg) gravityDewat. 0 2 2 2 2 2 2Time(min)Cake 57,5 57,42 57,31 57,23 57,21 55,5 54,1(Gram)Res Mois 13,04 12,92 12,76 12,63 12,60 9,86 7,49

%Saturation 1,000 0,989 0,975 0,964 0,961 0,729 0,540

70



27 Zircon Methanol .-150+200 50 0,44165%

Vacuum with 0,4 0,8 1 1,2(inch-Hg) gravityDewat. 0 2 2 2 2Time(min)Cake 57,41 57,35 57,3 56,89 54,8(Gram)Res Mois 12,91 12,82 12,74 12,11 8,76

%Saturation 1,000 0,992 0,985 0,930 0,648



28 Zircon Methanol .-150+200 50 0,45280%

Vacuum with 0,2 0,4 0,6 0,8 1(inch-Hg) gravityDewat. 0 2 2 2 2 2Time(min)Cake 57,44 57,35 57,27 57,21 57,15 54,6(Gram)Res Mois 12,95 12,82 12,69 12,60 12,51 8,41

%Saturation 1,000 0,988 0,977 0,969 0,961 0,617

71



29 Zircon Methanol .-150+200 50 0,46080%


%Saturation 1,000 0,989 0,974 0,963 0,962 0,721

Table A.30. -150+200 mesh zircon experimented with 5.10-5 M DA at pH 4


30 Zircon 10-5 M D .-150+200 50 0,485pH 4

Vacuum with 0,2 0,5 1 1,5 2 2,2(inch-Hg) gravityDewat. 0 2 2 2 2 2 2Time(min)Cake 60,01 60,01 59,99 59,99 59,98 56,4 55,7(Gram)Res Mois 33,34 33,34 33,32 33,32 33,31 29,03 28,12

%Saturation 1,000 1,000 0,998 0,998 0,997 0,635 0,564

72



31 Zircon 10-5 M D .-150+200 50 0,483pH 4


%Saturation 1,000 0,990 0,989 0,988 0,988 0,760 0,635



32 Zircon 10-5 M D .-150+200 50 0,451pH 6

Vacuum with 0,2 0,5 1 1,5 2 2,2(inch-Hg) gravityDewat. 0 2 2 2 2 2 2Time(min)Cake 58,75 58,75 58,72 58,71 58,7 57,7 57(Gram)Res Mois 31,91 31,91 31,88 31,87 31,86 30,66 29,76

%Saturation 1,000 1,000 0,997 0,995 0,994 0,879 0,794

73



33 Zircon 10-5 M D .-150+200 50 0,455pH 6


%Saturation 1,000 1,000 1,000 0,998 0,997 0,811 0,738



34 Zircon 10-5 M D .-150+200 50 0,443pH 8


%Saturation 1,000 0,999 0,998 0,995 0,993 0,839 0,667

74



35 Zircon 10-5 M D .-150+200 50 0,448pH 10

Vacuum with 0,2 0,5 1 1,5 1,8 2 2,2(inch-Hg) gravityDewat. 0 2 2 2 2 2 2 2Time(min)Cake 58,65 58,64 58,65 58,64 58,62 58,6 56,7 55,72(Gram)Res Mois 31,80 31,79 31,80 31,79 31,76 31,75 29,49 28,21

%Saturation 1,000 0,999 1,000 0,999 0,997 0,995 0,778 0,661



36 Zircon 10-5 M D .-150+200 50 0,452pH 10


%Saturation 1,000 0,999 0,999 0,999 0,999 0,998 0,814 0,778

75

Table A.37. -150+200 mesh zircon experimented with 10-5 M DA at pH 4


37 Zircon 10-5 M DA.-150+200 40 0,489pH 4


%Saturation 1,000 0,998 0,994 0,994 0,990 0,660 0,392



38 Zircon 10-5 M DA.-150+200 50 0,476pH 4


%Saturation 1,000 0,999 0,999 0,998 0,997 0,800 0,710

76



39 Zircon 10-5 M DA.-150+200 50 0,460pH 6


%Saturation 1,000 1,000 0,999 0,999 0,785 0,674 0,564



40 Zircon 10-5 M DA.-150+200 50 0,462pH 6

Vacuum with 0,2 0,5 1 1,5(inch-Hg) gravityDewat. 0 2 2 2 2Time(min)Cake 59,15 59,15 59,14 59,13 57,52(Gram)Res Mois 15,47 15,47 15,45 15,44 13,07

%Saturation 1,000 1,000 0,999 0,998 0,822

77



41 Zircon 10-5 M DA.-150+200 50 0,452pH 8


%Saturation 1,000 1,000 0,999 0,997 0,995 0,702 0,489



42 Zircon 10-5 M DA.-150+200 50 0,451pH 8

Vacuum with 0,2 0,5 1 1,5 2(inch-Hg) gravityDewat. 0 2 2 2 2 2Time(min)Cake 58,73 58,72 58,72 58,72 58,71 56,5(Gram)Res Mois 14,86 14,85 14,85 14,85 14,84 11,49

%Saturation 1,000 0,999 0,999 0,999 0,998 0,743

78



43 Zircon 10-5 M DA.-150+200 50 0,448pH 10

Vacuum with 0,2 0,5 1 1,5 1,8 2(inch-Hg) gravityDewat. 0 2 2 2 2 2 2Time(min)Cake 58,65 58,64 58,65 58,64 58,62 58,6 56,7(Gram)Res Mois 14,75 14,73 14,75 14,73 14,70 14,69 11,86

%Saturation 1,000 0,999 1,000 0,999 0,997 0,995 0,778



44 Zircon 10-5 M DA.-150+200 50 0,445pH 10

Vacuum with 0,2 0,5 1 1,5 1,8 2(inch-Hg) gravityDewat. 0 2 2 2 2 2 2Time(min)Cake 58,54 58,53 58,53 58,53 58,52 58,5 57(Gram)Res Mois 14,59 14,57 14,57 14,57 14,56 14,54 12,20

%Saturation 1,000 0,999 0,999 0,999 0,998 0,996 0,814

79

Table A.45. -150+200 mesh zircon experimented with 10-4 M SDS at pH 2


45 Zircon 0-4 M SD .-150+200 50 0,433pH 2


%Saturation 1,000 1,000 0,995 0,993 0,993 0,804 0,725 0,423



46 Zircon 0-4 M SD .-150+200 50 0,454pH 4


%Saturation 1,000 1,000 0,995 0,994 0,992 0,992 0,438 0,388

80



47 Zircon 0-4 M SD .-150+200 50 0,446pH 6


%Saturation 1,000 0,999 0,999 0,987 0,981 0,978 0,674 0,400



48 Zircon 0-4 M SD .-150+200 50 0,444pH 8


%Saturation 1,000 1,000 0,998 0,996 0,993 0,991 0,790 0,646

81

Table A.49. -150+200 mesh zircon experimented with 5.10-5 M SDS at pH 2


49 Zircon 10-5 M SD.-150+200 50 0,440pH 2

Vacuum with 0,2 0,5 1 1,5 1,8 2 2,5(inch-Hg) gravityDewat. 0 2 2 2 2 2 2 2Time(min)Cake 58,35 58,34 58,34 58,33 58,31 56,9 56 53,43(Gram)Res Mois 14,31 14,30 14,30 14,28 14,25 12,05 10,68 6,42

%Saturation 1,000 0,999 0,999 0,998 0,995 0,820 0,716 0,411



50 Zircon 10-5 M SD.-150+200 50 0,448pH 4


%Saturation 1,000 0,998 0,998 0,997 0,995 0,993 0,787 0,594

82



51 Zircon 10-5 M SD.-150+200 50 0,462pH 6


%Saturation 1,000 0,998 0,997 0,997 0,996 0,996 0,891 0,668



52 Zircon 10-5 M SD.-150+200 50 0,457pH 8

Vacuum with 0,2 0,5 1 1,5 1,8 2(inch-Hg) gravityDewat. 0 2 2 2 2 2 2Time(min)Cake 58,95 58,92 58,92 58,92 58,91 58,9 57,1(Gram)Res Mois 15,18 15,14 15,14 15,14 15,12 15,12 12,48

%Saturation 1,000 0,997 0,997 0,997 0,996 0,996 0,797

83



53 Zircon 0-5 M SD .-150+200 50 0,452pH 2

Vacuum with 0,2 0,5 1 1,5 2 2,5(inch-Hg) gravityDewat. 0 2 2 2 2 2 2Time(min)Cake 58,78 58,77 58,76 58,69 58,68 57 55,8(Gram)Res Mois 14,94 14,92 14,91 14,81 14,79 12,22 10,31

%Saturation 1,000 0,999 0,998 0,990 0,989 0,793 0,655



54 Zircon 0-5 M SD .-150+200 50 0,461pH 4

Vacuum with 0,2 0,5 1 1,5 1,8(inch-Hg) gravityDewat. 0 2 2 2 2 2Time(min)Cake 59,11 59,10 59,1 59,1 59,09 57,1(Gram)Res Mois 15,41 15,40 15,40 15,40 15,38 12,46

%Saturation 1,000 0,999 0,999 0,999 0,998 0,782

84



55 Zircon 0-5 M SD .-150+200 50 0,459pH 6

Vacuum with 0,2 0,5 1 1,5 1,8 2(inch-Hg) gravityDewat. 0 2 2 2 2 2 2Time(min)Cake 59,02 59,01 59,01 59,01 59,01 59 57,2(Gram)Res Mois 15,28 15,27 15,27 15,27 15,27 15,24 12,62

%Saturation 1,000 0,999 0,999 0,999 0,999 0,997 0,800



56 Zircon 0-5 M SD .-150+200 50 0,462pH 8


%Saturation 1,000 0,998 0,997 0,997 0,996 0,996 0,891 0,668

85

Table A.57. -150+200 mesh rutile experimented with water


57 Rutile Water .-150+200 50 0,441

Vacuum with 0,5 1 1,5 2 2,2 2,4 2,6(inch-Hg) gravityDewat. 0 2 2 2 2 2 2 2Time(min)Cake 59,39 59,36 59,35 59,27 59,12 58,8 55,1 54,2(Gram)Res Mois 15,81 15,77 15,75 15,64 15,43 14,89 9,32 7,75

%Saturation 1,000 0,997 0,996 0,987 0,971 0,932 0,547 0,447

Table A.58. -150+200 mesh rutile experimented with water


58 Rutile Water .-150+200 50 0,457

Vacuum with 0,2 0,4 0,6 0,7 0,8 1 1,2(inch-Hg) gravityDewat. 0 2 2 2 2 2 2 2Time(min)Cake 57,94 57,93 57,92 57,91 57,91 55,7 53,7 52,11(Gram)Res Mois 13,70 13,69 13,67 13,66 13,66 10,15 6,80 4,05

%Saturation 1,000 0,999 0,997 0,996 0,996 0,712 0,460 0,266

86

Table A.59. -150+200 mesh rutile experimented with methanol


59 Rutile Methanol .-150+200 50 0,468

Vacuum with 0,2 0,4 0,6 0,7 0,75 0,8 1(inch-Hg) gravityDewat. 0 2 2 2 2 2 2 2Time(min)Cake 58,31 58,22 58,14 58,03 58,03 58 55,2 54,12(Gram)Res Mois 14,25 14,12 14,00 13,84 13,84 13,81 9,44 7,61

%Saturation 1,000 0,989 0,980 0,966 0,966 0,964 0,627 0,496

Table A.60. -150+200 mesh rutile experimented with methanol


60 Rutile Methanol .-150+200 50 0,458

Vacuum with 0,2 0,4 0,6 0,7 0,75 0,8 1(inch-Hg) gravityDewat. 0 2 2 2 2 2 2 2Time(min)Cake 57,99 57,98 57,92 57,92 57,91 57,9 56,9 55,12(Gram)Res Mois 13,78 13,76 13,67 13,67 13,66 13,66 12,05 9,29

%Saturation 1,000 0,999 0,991 0,991 0,990 0,990 0,857 0,641

87

Table A.61. -150+200 mesh rutile experimented with 10% methanol


61 Rutile Methanol .-150+200 50 0,45410%

Vacuum with 0,5 1 1,5 1,8 2 2,2(inch-Hg) gravityDewat. 0 2 2 2 2 2 2Time(min)Cake 59,72 59,53 59,51 59,48 59,30 55,9 54,9(Gram)Res Mois 16,28 16,01 15,98 15,94 15,68 10,47 8,96

%Saturation 1,000 0,980 0,978 0,975 0,957 0,602 0,506



62 Rutile Methanol .-150+200 50 0,44310%

Vacuum with 0,5 1 1,5 1,8 2 2,2(inch-Hg) gravityDewat. 0 2 2 2 2 2 2Time(min)Cake 59,28 59,27 59,27 59,26 59,25 57,2 56,1(Gram)Res Mois 15,65 15,64 15,64 15,63 15,61 12,63 10,91

%Saturation 1,000 0,999 0,999 0,998 0,997 0,779 0,659

88



63 Rutile Methanol .-150+200 50 0,46725%

Vacuum with 0,5 1 1,2 1,4 1,6 1,8(inch-Hg) gravityDewat. 0 2 2 2 2 2 2Time(min)Cake 59,99 59,96 59,93 59,91 59,89 57 56,9(Gram)Res Mois 16,65 16,61 16,57 16,54 16,51 12,34 12,17

%Saturation 1,000 0,997 0,994 0,992 0,990 0,705 0,694



64 Rutile Methanol .-150+200 50 0,45825%


%Saturation 1,000 1,000 0,999 0,998 0,997 0,842 0,762

89



65 Rutile Methanol .-150+200 50 0,44440%


%Saturation 1,000 0,995 0,981 0,973 0,817 0,766 0,597



66 Rutile Methanol .-150+200 50 0,44940%

Vacuum with 0,5 1 1,2 1,4 1,6(inch-Hg) gravityDewat. 0 2 2 2 2 2Time(min)Cake 59,01 59,01 58,98 58,97 57,12 56,12(Gram)Res Mois 15,27 15,27 15,23 15,21 12,46 10,91

%Saturation 1,000 1,000 0,997 0,996 0,790 0,679

90



67 Rutile Methanol .-150+200 50 0,45950%

Vacuum with 0,4 0,6 0,8 1 1,1 1,2 1,4(inch-Hg) gravityDewat. 0 2 2 2 2 2 2 2Time(min)Cake 59,24 59,19 59,13 59,08 59,03 59 57,19 56,24(Gram)Res Mois 15,60 15,53 15,44 15,37 15,30 15,27 12,57 11,10

%Saturation 1,000 0,995 0,988 0,983 0,977 0,975 0,778 0,675



68 Rutile Methanol .-150+200 50 0,46650%

Vacuum with 0,4 0,6 0,8 1 1,2 1,4(inch-Hg) gravityDewat. 0 2 2 2 2 2 2Time(min)Cake 59,49 59,42 59,38 59,3 59,25 58,33 56,7(Gram)Res Mois 15,95 15,85 15,80 15,68 15,61 14,28 11,80

%Saturation 1,000 0,993 0,988 0,980 0,975 0,878 0,705

91



69 Rutile Methanol .-150+200 50 0,44565%

Vacuum with 0,2 0,4 0,6 0,8 1 1,2 1,4(inch-Hg) gravityDewat. 0 2 2 2 2 2 2 2Time(min)Cake 58,43 58,30 58,2 58,14 58,07 57,99 56,2 55,30(Gram)Res Mois 14,43 14,24 14,09 14,00 13,90 13,78 10,97 9,58

%Saturation 1,000 0,985 0,973 0,966 0,957 0,948 0,731 0,629



70 Rutile Methanol .-150+200 50 0,46365%

Vacuum with 0,2 0,4 0,6 0,8 1 1,2 1,4(inch-Hg) gravityDewat. 0 2 2 2 2 2 2 2Time(min)Cake 59,05 58,98 58,91 58,84 58,76 58,71 56,1 55,20(Gram)Res Mois 15,33 15,23 15,12 15,02 14,91 14,84 10,81 9,42

%Saturation 1,000 0,992 0,985 0,977 0,968 0,962 0,670 0,575

92



71 Rutile Methanol .-150+200 50 0,45780%

Vacuum with 0,2 0,4 0,6 0,8 1 1,2(inch-Hg) gravityDewat. 0 2 2 2 2 2 2Time(min)Cake 58,50 58,42 58,41 58,14 58,07 55,29 54,5(Gram)Res Mois 14,53 14,41 14,40 14,00 13,90 9,57 8,29

%Saturation 1,000 0,991 0,989 0,958 0,949 0,622 0,532



72 Rutile Methanol .-150+200 50 0,47280%


%Saturation 1,000 0,999 0,998 0,996 0,993 0,679

93

Table A.73. -150+200 mesh rutile experimented with 10-4 M DA at pH 4


73 Rutile 10-4 M DA.-150+200 50 0,445pH 4


%Saturation 1,000 0,887 0,886 0,885 0,883 0,748 0,646 0,604



74 Rutile 10-4 M DA.-150+200 50 0,447pH 4


%Saturation 1,000 0,999 0,998 0,997 0,996 0,795 0,648 0,599

94



75 Rutile 10-4 M DA.-150+200 50 0,438pH 6

Vacuum with 0,5 1 1,5 2 2,1 2,2(inch-Hg) gravityDewat. 0 2 2 2 2 2 2Time(min)Cake 59,28 58,35 58,35 58,32 58,30 57,32 56,45(Gram)Res Mois 24,09 22,88 22,88 22,84 22,81 21,49 20,28

%Saturation 1,000 0,900 0,900 0,897 0,894 0,789 0,695



76 Rutile 10-4 M DA.-150+200 50 0,438pH 6


%Saturation 1,000 0,900 0,900 0,897 0,894 0,789 0,695

95



77 Rutile 10-4 M DA.-150+200 50 0,435pH 8


%Saturation 1,000 0,999 0,997 0,996 0,995 0,781 0,573



78 Rutile 10-4 M DA.-150+200 50 0,430pH 8


%Saturation 1,000 1,000 0,999 0,999 0,999 0,819 0,570

96



79 Rutile 10-4 M DA.-150+200 50 0,438pH 10


%Saturation 1,000 1,000 1,000 0,999 0,995 0,992 0,661



80 Rutile 10-4 M DA.-150+200 50 0,435pH 10


%Saturation 1,000 0,998 0,998 0,995 0,993 0,988 0,778

97

Table A.81. -150+200 mesh rutile experimented with 5.10-5 M DA at pH 4


81 Rutile 10-5 M DA.-150+200 50 0,433pH 4


%Saturation 1,000 0,998 0,998 0,997 0,996 0,990 0,841



82 Rutile 10-5 M DA.-150+200 50 0,438pH 4

Vacuum with 0,5 1 1,5 2 2,2 2,4(inch-Hg) gravityDewat. 0 2 2 2 2 2 2Time(min)Cake 59,26 59,25 59,21 59,19 59,18 59,17 58(Gram)Res Mois 24,06 24,05 24,00 23,97 23,96 23,95 22,43

%Saturation 1,000 0,999 0,995 0,992 0,991 0,990 0,865

98



83 Rutile 10-5 M DA.-150+200 50 0,447pH 6


%Saturation 1,000 0,995 0,994 0,994 0,992 0,888 0,738



84 Rutile 10-5 M DA.-150+200 50 0,449pH 6

Vacuum with 0,5 1 1,5 2 2,2(inch-Hg) gravityDewat. 0 2 2 2 2 2Time(min)Cake 59,69 59,68 59,67 59,67 59,64 57,99(Gram)Res Mois 24,61 24,60 24,59 24,59 24,55 22,40

%Saturation 1,000 0,999 0,998 0,998 0,995 0,825

99


TEST NO TEST TEST SIZE Y SOLIDSCAKE POROSITYSOLIDS LIQUID (MESH) (GRAM)

85 Rutile 10-5 M DA.-150+200 50 0,444pH 8


%Saturation 1,000 1,000 0,997 0,996 0,994 0,776 0,655


TEST NO TEST TEST SIZE Y SOLIDSCAKE POROSITYSOLIDS LIQUID (MESH) (GRAM)

86 Rutile 10-5 M DA.-150+200 50 0,443pH 8


%Saturation 1,000 0,998 0,997 0,997 0,997 0,661 0,542

100



87 Rutile 10-5 M DA.-150+200 50 0,441pH 10


%Saturation 1,000 0,998 0,991 0,990 0,988 0,988 0,753



88 Rutile 10-5 M DA.-150+200 50 0,434pH 4

Vacuum with 0,5 1 1,5 2 2,2 2,4(inch-Hg) gravityDewat. 0 2 2 2 2 2 2Time(min)Cake 59,11 59,01 59,01 59,01 58,97 59 57,8(Gram)Res Mois 15,41 15,27 15,27 15,27 15,21 15,21 13,48

%Saturation 1,000 0,989 0,989 0,989 0,985 0,985 0,855

101



89 Rutile 10-5 M DA.-150+200 50 0,430pH 4


%Saturation 1,000 0,998 0,997 0,996 0,996 0,991 0,851



90 Rutile 10-5 M DA.-150+200 50 0,428pH 6


%Saturation 1,000 0,998 0,997 0,997 0,994 0,994 0,722

102



91 Rutile 10-5 M DA.-150+200 50 0,431pH 6


%Saturation 1,000 1,000 0,999 0,998 0,983 0,982 0,852



92 Rutile 10-5 M DA.-150+200 50 0,432pH 8

Vacuum with 0,5 1 1,5 2 2,2 2,4(inch-Hg) gravityDewat. 0 2 2 2 2 2 2Time(min)Cake 59,07 59,06 59 58,98 58,97 58,9 57(Gram)Res Mois 15,35 15,34 15,25 15,23 15,21 15,05 12,22

%Saturation 1,000 0,999 0,992 0,990 0,989 0,977 0,767

103



93 Rutile 10-5 M DA.-150+200 50 0,435pH 8


%Saturation 1,000 0,999 0,996 0,996 0,995 0,991 0,857



94 Rutile 10-5 M DA.-150+200 50 0,440pH 10


%Saturation 1,000 0,998 0,997 0,997 0,995 0,991 0,794

104



95 Rutile 10-5 M DA.-150+200 50 0,442pH 10


%Saturation 1,000 0,997 0,997 0,995 0,994 0,993 0,860

Table A.96. -150+200 mesh rutile experimented with 10-4 M SDS at pH 2


96 Rutile 0-5 M SD .-150+200 50 0,428pH 2

Vacuum with 0,5 1 1,5 2 2,2(inch-Hg) gravityDewat. 0 2 2 2 2 2Time(min)Cake 58,89 58,85 58,85 58,86 57,16 56,1(Gram)Res Mois 15,10 15,04 15,04 15,05 12,53 10,92

%Saturation 1,000 0,996 0,996 0,997 0,805 0,690

105



97 Rutile 0-4 M SD .-150+200 50 0,439pH 4


%Saturation 1,000 0,999 0,996 0,994 0,994 0,992 0,779



98 Rutile 0-4 M SD .-150+200 50 0,443pH 6


%Saturation 1,000 0,997 0,995 0,995 0,995 0,992 0,756

106



99 Rutile 0-4 M SD .-150+200 50 0,434pH 8


%Saturation 1,000 0,999 0,999 0,999 0,996 0,996 0,836

Table A.100. -150+200 mesh rutile experimented with 5.10-5 M SDS at pH 2


100 Rutile 10-5 M SD.-150+200 50 0,441pH 2


%Saturation 1,000 0,999 0,999 0,998 0,870 0,762 0,659

107



101 Rutile 10-5 M SD.-150+200 50 0,457pH 4


%Saturation 1,000 0,998 0,996 0,992 0,991 0,991 0,872



102 Rutile 10-5 M SD.-150+200 50 0,454pH 6


%Saturation 1,000 0,997 0,995 0,995 0,994 0,993 0,761

108



103 Rutile 10-5 M SD.-150+200 50 0,450pH 8

Vacuum with 0,5 1 1,5 2 2,2 2,4(inch-Hg) gravityDewat. 0 2 2 2 2 2 2Time(min)Cake 59,73 59,72 59,72 59,71 59,69 59,7 58(Gram)Res Mois 16,29 16,28 16,28 16,26 16,23 16,22 13,78

%Saturation 1,000 0,999 0,999 0,998 0,996 0,995 0,821



104 Rutile 0-5 M SD .-150+200 50 0,437pH 2


%Saturation 1,000 1,000 0,999 0,998 0,998 0,831 0,618

109



105 Rutile 0-5 M SD .-150+200 50 0,436pH 4


%Saturation 1,000 0,999 0,998 0,992 0,991 0,991 0,781



106 Rutile 0-5 M SD .-150+200 50 0,438pH 6


%Saturation 1,000 0,996 0,996 0,995 0,994 0,992 0,879

110



107 Rutile 0-5 M SD .-150+200 50 0,444pH 8


%Saturation 1,000 0,995 0,994 0,993 0,989 0,988 0,834

111

APPENDIX B

TABLES OF COLUMN WICKING EXPERIMENTS

Table B.1. -150+200 mesh zircon experimented with water

TEST NO : 109 TEST NO : 110seconds cm seconds cm

10 1,8 10 1,820 2,6 20 2,630 3,4 30 3,240 3,9 40 3,650 4,4 50 3,960 4,6 60 4,170 4,9 70 4,480 5,4 80 4,690 5,6 90 4,8100 5,8 100 5110 6 110 5,2

120 5,4

Table B.2. -150+200 mesh zircon experimented with methanol


10 2 10 220 3,1 20 330 3,9 30 3,640 4,6 40 4,250 5,1 50 4,760 5,6 60 5,170 6,1 70 5,680 6,5 80 5,890 6,8 90 6,2100 7,2 100 6,6110 7,4 110 6,8120 7,7 120 7,2130 8,1 130 7,4140 8,2 140 7,8150 8,5 150 8160 8,7170 8,8

112

Table B.3. -150+200 mesh zircon experimented with hexane

TEST NO : 113seconds cm

10 020 030 040 050 060 070 080 090 0100 0110 0120 0

Table B.4. -150+200 mesh zircon experimented with formamide


10 1,1 10 1,120 1,8 20 1,830 2,2 30 2,440 2,6 40 2,850 2,8 50 360 3,2 60 3,270 3,4 70 3,680 3,6 80 3,790 3,8 90 3,8100 4 100 4

113

Table B.5. -150+200 mesh zircon experimented with 10% methanol


10 1,4 10 1,420 2,2 20 2,130 2,7 30 2,740 3,2 40 3,250 3,6 50 3,660 4 60 3,970 4,2 70 4,280 4,4 80 4,390 4,6 90 4,6100 4,9 100 4,8110 5,2



10 1,4 10 1,520 2,3 20 2,330 2,7 30 2,740 3,1 40 350 3,5 50 3,360 3,8 60 3,770 4 70 480 4,2 80 4,390 4,4 90 4,5


TEST NO : 120 TEST NO : 121seconds cm t cm

10 1,5 10 1,620 2,2 20 2,330 2,6 30 2,740 3,1 40 3,250 3,6 50 3,760 3,9 60 4,170 4,2 70 4,480 4,3 80 4,790 4,6 90 5100 5 100 5,3

114



10 1,4 10 1,520 2 20 2,130 2,6 30 2,640 3 40 350 3,4 50 3,460 3,7 60 3,670 4 70 480 4,4 80 4,390 4,6 90 4,6100 4,8 100 4,9110 5 110 5,1



10 1,4 10 1,520 2,2 20 2,330 2,8 30 2,840 3,4 40 3,550 3,8 50 3,960 4,2 60 4,270 4,6 70 4,580 4,9 80 4,890 5,1 90 5,2100 5,4 100 5,5110 5,6 110 5,8120 5,8 120 6,1

115



10 1,6 10 1,520 2,2 20 2,330 2,8 30 2,840 3,2 40 3,250 3,6 50 3,660 4,2 60 470 4,4 70 4,380 4,9 80 4,690 5,2 90 4,9100 5,5 100 5,3110 5,8 110 5,6

Table B.11. -150+200 mesh zircon experimented with 5.10-5 M DA at pH 4


10 1,6 10 1,520 2 20 2,130 2,3 30 2,340 2,6 40 2,750 2,9 50 360 3,1 60 3,270 3,4 70 3,480 3,6 80 3,690 3,8 90 3,8100 4,1 100 4110 4,4 110 4,1120 4,6 120 4,3

116



10 1,4 10 1,420 1,8 20 1,730 2 30 240 2,2 40 2,350 2,4 50 2,560 2,6 60 2,770 2,8 70 2,980 3 80 3,190 3,25 90 3,3100 3,4 100 3,4110 3,7 110 3,6120 3,8 120 3,9



10 1,4 10 1,320 1,6 20 1,530 1,8 30 1,740 2 40 1,950 2,2 50 2,160 2,4 60 2,370 2,55 70 2,580 2,7 80 2,690 2,8 90 2,7100 2,9 100 3110 2,95 110 3,2120 3,1 120 3,3

117



10 1,65 10 1,620 2,4 20 2,430 3,1 30 3,140 3,6 40 3,550 4,1 50 3,860 4,3 60 4,270 4,6 70 4,680 4,9 80 590 5,1 90 5,3100 5,3 100 5,5110 5,6 110 5,8120 5,78 120 6

Table B.15. -150+200 mesh zircon experimented with 10-5 M DA at pH 4


10 1,6 10 1,620 2,3 20 2,230 3 30 2,640 3,4 40 3,150 3,8 50 3,660 4,1 60 470 4,3 70 4,480 4,5 80 4,890 4,7 90 5,1100 5 100 5,4110 5,2 110 5,5120 5,4 120 5,7

118



10 1,5 10 1,520 2 20 230 2,4 30 2,440 2,6 40 2,650 2,8 50 2,960 3 60 3,170 3,2 70 3,380 3,4 80 3,590 3,5 90 3,7100 3,6 100 4110 3,65 110 4,1



10 1,4 10 1,520 1,9 20 1,930 2,2 30 2,240 2,4 40 2,450 2,6 50 2,760 2,8 60 2,970 3 70 3,180 3,15 80 3,290 3,25 90 3,3100 3,3 100 3,4110 3,4 110 3,5

119



10 1,8 10 1,720 2,3 20 2,230 3,1 30 340 3,6 40 3,550 4 50 3,960 4,4 60 4,470 4,7 70 4,680 5 80 4,890 5,2 90 5100 5,6 100 5,3110 5,8

Table B.19. -150+200 mesh zircon experimented with 10-5 M SDS at pH 2

TEST NO 144 TEST NO : 145seconds cm seconds cm

10 1,6 10 1,520 2,4 20 2,330 2,9 30 340 3,3 40 3,250 3,7 50 3,560 3,95 60 3,870 4,1 70 4,280 4,4 80 4,590 4,6 90 4,6100 4,75 100 4,8

120

Table B.20. -150+200 mesh zircon experimented with 5.10-5 M SDS at pH 2


10 1,4 10 1,420 2 20 230 2,4 30 2,440 2,8 40 2,750 3,1 50 2,960 3,3 60 3,270 3,7 70 3,680 4 80 3,990 4,3 90 4,2100 4,6 100 4,4110 4,7 110 4,7120 4,8 120 5

Table B.21. -150+200 mesh zircon experimented with 10-4 M SDS at pH 2

TEST NO 148 TEST NO : 149seconds cm seconds cm

10 1,2 10 1,320 1,6 20 1,730 2 30 240 2,3 40 2,350 2,6 50 2,660 2,8 60 2,970 3 70 3,180 3,2 80 3,390 3,4 90 3,5100 3,6 100 3,7110 3,7 110 3,8120 3,8 120 3,9

121

Table B.22. -150+200 mesh rutile experimented with water


10 1,6 10 1,620 2,4 20 2,430 3 30 340 3,6 40 3,450 3,9 50 3,860 4,2 60 4,270 4,6 70 4,680 4,8 80 4,890 5 90 5100 5,2 100 5,4110 5,5 110 5,5120 5,6 120 5,6130 5,8 130 5,9140 6 140 6150 6,1 150 6,2160 6,4 160 6,4170 6,6 170 6,6

122

Table B.23. -150+200 mesh rutile experimented with methanol


10 1,7 10 1,620 2,6 20 2,430 3,2 30 3,140 3,8 40 3,750 4,2 50 4,160 4,7 60 4,570 5 70 4,980 5,4 80 5,390 5,8 90 5,7100 6,1 100 5,8110 6,4 110 6,2120 6,6 120 6,5130 6,9 130 6,7140 7,1 140 7150 7,3 150 7,2160 7,5 160 7,4170 7,7 170 7,6180 7,9 180 7,8190 8,1 190 8200 8,3210 8,4

Table B.24. -150+200 mesh rutile experimented with 10% methanol


10 1,4 10 1,520 1,8 20 1,830 2,1 30 2,240 2,4 40 2,550 2,7 50 2,860 3 60 370 3,2 70 3,380 3,4 80 3,590 3,6 90 3,6

123



10 1 10 1,320 1,8 20 1,930 2,3 30 2,440 2,6 40 2,750 3 50 3,160 3,4 60 3,470 3,6 70 3,780 3,9 80 490 4,1 90 4,2100 4,4 100 4,4



10 1 10 1,220 1,6 20 1,730 2,2 30 2,240 2,6 40 2,650 2,9 50 360 3,1 60 3,370 3,5 70 3,680 3,8 80 3,890 4 90 4,1

124



10 1,4 10 1,420 2 20 230 2,5 30 2,540 2,9 40 350 3,2 50 3,360 3,6 60 3,670 3,8 70 480 4 80 4,390 4,3 90 4,6100 4,5 100 4,9110 4,8 110 5,1120 4,9 120 5,3



10 1,4 10 1,420 2,1 20 2,130 2,6 30 2,740 3 40 350 3,4 50 3,360 3,8 60 3,770 4 70 480 4,2 80 4,390 4,4 90 4,5100 4,6 100 4,7110 4,8120 5

125



10 1,5 10 1,420 2,3 20 2,230 2,9 30 2,940 3,3 40 3,350 3,8 50 3,860 4,1 60 4,170 4,4 70 4,380 4,6 80 4,790 5 90 4,9100 5,2 100 5

Table B.30. -150+200 mesh rutile experimented with 10-4 M DA at pH 4


10 1,75 10 1,720 2,15 20 2,230 2,4 30 2,640 2,7 40 2,950 3 50 3,160 3,3 60 3,570 3,45 70 3,780 3,7 80 3,9



10 1,5 10 1,420 1,75 20 1,830 2 30 2,240 2,15 40 2,550 2,3 50 2,860 2,5 60 3,170 2,6 70 3,480 2,7 80 3,690 2,8 90 3,8100 2,85110 2,95120 3

126



10 1,6 10 1,620 2 20 230 2,25 30 2,340 2,5 40 2,650 2,7 50 2,860 2,9 60 370 2,95 70 3,2



10 1,7 10 1,620 2,3 20 2,330 2,8 30 2,940 3,3 40 3,250 3,7 50 3,560 4 60 3,870 4,3 70 4

Table B.34. -150+200 mesh rutile experimented with 5.10-5 M DA at pH 4


10 220 2,430 2,840 3,150 3,460 3,670 3,7580 3,990 3,9100 4,05

127


TEST NO : 175t cm

10 1,720 230 2,2540 2,4550 2,660 2,870 3,180 3,2



10 1,9520 2,330 2,4540 2,750 2,960 3,170 3,480 3,6



10 2,120 2,630 340 3,450 3,860 4,270 4,35

128



10 1,520 2,130 2,640 350 3,360 3,770 4,180 4,4



10 1,6520 230 2,240 2,450 2,6560 2,8570 3,1580 3,390 3,45



10 1,720 2,130 2,3540 2,650 2,960 3,270 3,55

129



10 1,720 2,3530 2,7540 3,250 3,660 470 4,3

130

APPENDIX C

TABLES OF MICROFLOTATION EXPERIMENTS

Table C.1. -150+200 mesh zircon experimented with water

recovery, % tailing, %91 993 791 990 192 8

Table C.2. -150+200 mesh zircon experimented with 10-3 M DA at different pH values

pH 4 pH 6recovery, % tailing, % recovery, % tailing, %

38 62 93 744 56 91 9


89 11 18 8294 6 16 84



24 76 52 4821 79 49 51


54 46 15 8557 43 13 87

131

Table C.4. -150+200 mesh zircon experimented with 5.10-5 M DA at different pH values


11 89 28 7215 85 31 69


32 68 11 8931 69 9 91



3 97 9 915 95 4 96


7 93 1 995 95 6 94

Table C.6. -150+200 mesh zircon experimented with 10-3 M SDS at different pH values


92 8 19 8189 11 16 84


2 98 5 953 97 6 94



78 22 5 9574 26 4 96


0 100 5 952 98 3 97

132

Table C.8. -150+200 mesh zircon experimented with 5.10-5 M SDS at different pH values


62 38 9 9158 42 7 93


4 96 0,03 0,971 99 0 1



17 83 1 9923 77 2 98


5 95 6 943 97 4 96

Table C.10. -150+200 mesh rutile experimented with 10-3 M DA at different pH values


45 55 88 1242 58 92 8


91 9 25 7585 15 34 66



18 82 54 4622 78 47 53


45 55 15 8541 59 12 88

133

Table C.12. -150+200 mesh rutile experimented with 5.10-5 M DA at different pH values


13 87 35 6515 85 29 71


25 75 6 9428 72 9 91



5 95 12 883 97 13 87


9 91 3 977 93 2 98

Table C.14. -150+200 mesh rutile experimented with 10-3 M SDS at different pH values


91 9 6 9493 7 8 92


2 98 4 964 96 7 93



88 12 3 9792 8 5 95


2 98 4 966 94 4 96

134

Table C.16. -150+200 mesh rutile experimented with 5.10-5 M SDS at different pH values


25 75 6 9423 77 3 97


3 97 2 984 96 4 96



12 88 4 9615 85 1 99


5 95 1 993 97 3 97

135

APPENDIX D

TABLES OF CONTACT ANGLES OBTAINED FROM CAPILLARIC DEWATERING EXPERIMENTS WITH REPEAT TESTS

Table D.1.The reproducibilty of -150+200 mesh zircon experimented with 10% methanol

Experiment 1 Experiment 239.42 37.69









136



Table D.7.The reproducibilty of -150+200 mesh zircon experimented with 5.10-5 M DA at pH 4








Table D.11.The reproducibilty of -150+200 mesh zircon experimented with 10-5 M DA at pH 4


137







Table D.15.The reproducibilty of -150+200 mesh rutile experimented with water


Table D.16.The reproducibilty of -150+200 mesh rutile experimented with 10% methanol






138





Table D.21.The reproducibilty of -150+200 mesh rutile experimented with10-4 M DA at pH 4








Table D.25.The reproducibilty of -150+200 mesh rutile experimented with 5.10-5 M DA at pH 4


139





140

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